I got 6.084 for the chi square value. The degree of freedom is 1, and referring to the table, I reject the null hypotesis. Thankyou, Mr. Andersen! This is very helpful! :)
@@leerim2455 he means that we cannot reject it. Not rejecting it does not exactly mean that the statement is accurate. We are just stating that it is not necessarily wrong
My chi square results was 6.084. Since the degree of freedom is 1, the critical value under the 0.05 column is 3.841. Since 6.084 is larger than 3.841, the null hypotheses is rejected. There is relationship between the variables in the hypotheses.
I am a one of those students that has to learn on RUclips. Thank you for having done these videos you are saving my brain from a slow and painful death. This bio Golden Bear sure appreciates you. It is difficult not being at the university to have someone explain in person. You rock! I hope that only good things come your way. I was feeling stupid over this, but then I came upon your video and realized I have done this in my anthropology classes. My brain feels 1000x's smarter. Thanks to you
Started skipping my stats class because I was frustrated with the teacher, I just wasn't understanding it the way she was teaching it. He literally just perfectly explained in 11 minutes what took her 3 weeks to do and I actually understood it.
I first heard about Chi Squared in 1987.. As an undergraduate. It took you 11 minutes to teach me what I couldn't grasp in 27 years! Bravo to you .. I want a refund for my tuition fees
Today was my first day of AP Bio and my teacher assigned us to watch this video and take notes. The answer to the pill bugs question at the end is no, we can accept but REJECT the fact that there is a difference between what was expected and what was observed. The degree of freedom is 1 since there are two outcomes (and 2-1 is 1 according to the steps to determine the degree of freedom in an experiment). Then, when you write out the formulas and add them together, you get 6.084 as your chi-value. Since the degree of freedom is 1, you would have to look at 3.841 under the 0.05 column. Since 6.084 is greater than this number, we must reject the null hypothesis.
My AP test is tomorrow and I knew essentially all I needed to know about AP Bio except for Chi-Squared tests, but thanks to you I actually get it. So thank you for saving my life.
you are my lifeline kind sir, my worksheet and textbook combined looked SO threatening, turns out its this simple. my entire education is built upon the foundation of RUclips channels like yours 🙏🙏🙏
I'm a school kid who struggles with maths. I study biology however and finally understand this and did the problem the end. Thank you Paul and people in the comments who I checked my answer with!
+AllGoodsGee In statistics we're taught to say fail to reject because that doesn't necessarily mean we're accepting the null hypothesis. I think the entire argument is tailored around the whole "causation does not imply correlation" idea
Truly this man is my actual AP Bio teacher. My real one doesn't know how to teach and just recites the exact words out of the textbook. I thank god for having this man to guide me through such a hard class
The clearest explanation I have seen on Chi Square. At work I use it to insure the uptake probe is working properly. I finally have a clear understanding of the significance of our daily test. Thank YOu.
10.647 With the degrees of freedom being 1 and the point of significance being 0.05 The independent variable does have an effect on the dependent variable
Statistics exam in 4 days and I feel like I know nothing. None of my lectures were clear and the whole class are scared. Thank you for uploading these. They may actually make the difference between me becoming a psychologist or not. SO grateful
It is very important that you never accept a null hypothesis but rather you fail to reject it. I am in Ap statistics and I have have been taught that is a big no-no. They mean basically the same thing but accepting the null might indicate causation.
I got Chi squared = 6.084. And since we have only 2 options, so the degree of freedom = 1. For a critical value of 3.841 (i.e. 0.05 accuracy column), hence, the null hypothesis is rejected in this case!
I am a Biology and Chemistry major and get almost everything but some things, the professors have trouble explaining or go through it way too fast or the book makes it more complicated than what it is and then i come to you and everything makes so much sense!! You are amazing, thank you for being smart and helping me for the past 4 years
Yes, the chi-square value is 6.084 and it is greater than the 3.841 rejection value at .05. Therefore, we can say that our observed data fails the test. Another way of saying it is that the null hypothesis fails.
Got this video linked by a friend in preparation for my math exam at uni and holy shit, this helped me understand the test so much better than how my professor did it. The way he explained it made no sense and yours I understood by watching it once despite English not being my primary language nor the language of my classes. Thank you so much! You are wonderful at explaining!
Thanks, I really needed this. I completely forgot how to do Chi Square and I have a Biology quiz tomorrow :) For that last one on Animal Behavior I got 6.084 and I rejected my null hypothesis because I think the Degree of Freedom (1) has a Critical Value of 3.841 in the 95% column. ^_^
Revisiting this channel after I first did in 2019. This particular lesson helped me obtained A+ in my statistic exam in L200 and I am back here to say thank you
Nooooooo, 30 is for central limit theorem to suggest that the sampling distribution is normal, this is a chi-square test, you should look for at least 5 expected counts for each observation :(((
Brilliantly explained...It's all coming back to me from years ago at school. Thanks for choosing simple examples of flipping a coin and rolling dice; then building on that. Most videos start with complicated research hypotheses, which may be largely irrelevant to people interested in pure probability and chance.
Wow, thank you soooooo much! I was trying to figure out what my textbook was saying, however it was totally a waste of time, how could I understand without any examples or even graphs on my textbook? You made it easy for me! Good job, and thank you a lot!
I've failed my Statistics class once, second time going now, 2 Lecturers have attempted teaching me Chi Squares.. well not blaming their methods, but finally I understood this! Thank you good sir!!
null hypothesis rejected because the critical value is 3.841 and the chi-squared value is 6.084. there is a significant difference between pill bugs spending time in wet versus dry places
My teacher just sped through chi squared as a whole just to spite me bc I joined AP bio...He didn't want me to but I did anyways so I came here to actually learn it. It really helped and I got a 6.084 so deny that using the null hypothesis
_Here is the answer with steps to how to do it if any of y'all need it from the future, past, or present!_ Wet + Dry Xctotal^2 = Xc^2Wet + Xc^2Dry Xc^2= [ (Oi-Ei)^2/ Ei ] + [ (Oi-Ei)^2/ Ei ] Xc^2= [ (8.9-5)^2 / 5 ] + [ (1.1-5)^2 / 5 ] Xc^2= ( 15.21 / 5 ) + ( 15.21 / 5 ) Xc^2= 30.42 / 5 Xc^2= 6.084 Degrees of Freedom = (N1+N2)- 1 = 2-1 = 1. Critical Value = 0.05 Final chart value = 3.841 *_6.084 is greater than 3.841_* *_Hence the Null value is rejected._* _You're Welcome._ 😊👌
so whats the answer? Cause I got my chi square value to be 6.084, degree of freedom to be 1 and using critical value of .05 I ended up rejecting the null hypothesis
Fuad David Actually, there are only two outcomes: wet or dry. 2 - 1 is 1, so you use the first degree of freedom. The expected values don't matter when figuring that part.
ERROR IN THE CHI-SQUARE ANALYSIS? I love Mr. Anderson’s videos and frequently recommend them to my students and fellow teachers. As a first year AP Biology teacher, I have relied heavily on his help for explaining the labs that we have done. However when my students did the pill bug experiment, we didn’t get results that were as clear cut in giving a chi-square critical value that allowed us to reject the null hypothesis. We went back to the lab and gathered more data and still had the same problem. It looked like there was a difference but the chi-square critical value was still below the threshold for rejecting the null hypothesis, so I began to examine the analysis. I don’t have a good background in statistics so I went to a publication by BioInteractive, on the HHMI.org site, Mathematics and Statistics in Biology, written by Paul Strode, PhD, and Ann Brokaw. A statement for p.21 caught my eye, “Note that this test must be used on raw categorical data. Values need to be simple counts, not percentages or proportions. The size of the sample is an important aspect of the chi-square test-it is more difficult to detect a statistically significant difference between experimental and observed results in a small sample than in a large sample.” www.hhmi.org/biointeractive/teacher-guide-math-and-statistics By adding up the columns (excluding the first data points at time =0) instead of taking the average, we get chi-square value of 73.96. This is extreme in this case, as the preference of the pill bugs is very clear, but using the raw data allows us to reject the null hypothesis in much less obvious sets of data. This also helps illustrate the debate in the comments here about “accepting” vs. “not rejecting” the null hypothesis. If the chi-square value is below the critical value, we may “not reject the null hypothesis;” however, we cannot accept it either because, as was the case in my classes, collecting more data which reflects a small difference becomes significant once the data pool becomes large enough. This is my understanding of the real value of the chi-square test in telling us when we have found a significant difference in results.
Great explanation! Lecture was 2 hours long and you did it all in a 12 mins video! Saved me from watching a 2 hours long lecture recapture.. thanks a a lot for all the effort!
Cry... Actually this just means your data is right on the cusp of being considered skewed by a variable. So it COULD be chance (technically it can always be chance) but it's fairly unlikely
In science, we typically want to be on the sure side of things. If your data happens to be right on the critical value, you'd probably want to take more data. Or, you can simply report that your data had a p-value of 5%.
You reject your null hypothesis because you are 95% sure that the data value is less than the critical value, and 94.99999% for anything equal to or above it
For pill bugs, the chi-square is 6.084 using the data, and since there is 1 degree of freedom (2 different variations MINUS one) and the critical value for that degree of freedom is 6.314 in the 0.05 column, the chi-sq is less than the critical so you must ACCEPT the null hypothesis (and you know there isn't any outside force that affected your data and there isn't a large difference between your expected and observed data.
Over the past 12 weeks in my bio lab I've been copying other peoples work because I didn't understand this, now it makes perfect sense to me. Taking my final today and I should have no problem with these questions. Chi Square = 6.084 | degree of freedom was 1 so the critical value = 3.84 and there for its evident that there was a significant difference between our expected and observed values. Hence.... something was definitely causing those bugs to prefer the wet environment! wooot!
Mr. Anderson, I first saw you my sophomore year of high school for AP Bio help, now as a college junior I was so happy to see this video pop up for a refresher stats lesson
Chi Square value is 6.084 and our critical chi square value is 3.84. Since the chi square value is more than critical value, there is a significant difference in Animals spending time in wet and dry places. Am I correct?
+Siddu Kolli I have a question. In my book it says on the Chi Square table that: The calculated value must be equal to or less than the critical value for significance to be shown. If 'significance' means 'difference' and 'Difference' means 'rejecting' the null hypothesis, Why is it that 6.084 which is higher than 3.841 rejecting the null? Isn't it supposed to be accepting it, since the calculated value is higher? *confused.
+Random Leaner 3.841 is the critical value when the degree of freedom equals one. With the pill bug data the actual degree of freedom is 10-1=9 (10 being the number of pill bugs). On the chart, the critical value point would then be on row 9 under .05 which is 16.919. This makes it less then Chi-Square value which makes us accept the null hypothesis.
so the correct answer is to accept the null hypothesis right? because the degree of freedom should be 10-1. i almost got confused looking at some other answers, thinking we had to consider wet/dry as i was wondering how they got their critical value as 3.841
+Jess Lee Remember that there are only 2 outcomes. So degree of freedom would be 1. Also, the null hypothesis for Chi Square tests is that there is no difference. So we reject the null if the obtained chi square statistic is above the critical chi square statistic
Someone give this man a medal for his ability to explain this in such a simple and easily understood manner!
His a good guy
I wish I'd taken stats from a scientist instead of a mathematician
Strongly agree 💙
strongly agree!
🥇🏆🙏
I got 6.084 for the chi square value. The degree of freedom is 1, and referring to the table, I reject the null hypotesis. Thankyou, Mr. Andersen! This is very helpful! :)
Thanks for sharing, I got the same, this way I can confirm that my calculations were right
great, i got the same 👍
Same.
I wish my teacher was as clear and thorough as you are.
Thanks for all your help.
my teacher showed this video instead of teaching
Same here
SAMETF\
Ophelia Ho hi
I'm here teaching myself genetics because my professor refuses to teach us. Thank god for RUclips.
Some people in this world are blessed with the gift of being an amazing teacher and you are certainly one of them! Thank you for all your help!
Also, people who were lucky enough to be their students!
We don't accept the null hypothesis... We only fail to reject it
+fahmyboy1 the definition of accept also to recognize so his statement is valid
PREACH. Who's mans is this?!
he's right
@@leerim2455 he means that we cannot reject it. Not rejecting it does not exactly mean that the statement is accurate. We are just stating that it is not necessarily wrong
woke
Goddamnit why am I taking bio AP
+seven werd
because its the best thing ever.
I never actually got to take it which was a total bummer, so good for you!
+MegaAimPoint I believe in you! ypu can totally do it!! study hard love!!
+seven werd
LOL same!!!!! idk why I took this class, homeworks got me stressing all the time. Idk why I thought this was going to be fun...
+Sirius Black ikr? i really don't like it...
same. Our teacher gave us a packet on this and she didn't explain very much. It was a pain finishing it.
When you sped up the video for the dice probability one, that was the most jamtastic math sequence ever
agreed
Paul glad you agree Sasuke
Didnt pay attention the whole chapter over chi squared and hardy-Weinberg just spent 30 minutes looking at your videos and got an a on the test.
Same here thought this Topic is damn tough turns out to be an easy delicious free food in exam :)
Tenzin Palden mmm
The degrees of freedom is the number of choices (i.e. Heads or Tails) minus one. Therefore the degrees of freedom is on. Hope this helps.
Where can I find the chart you used??
AP Bio Test tomorrow. I hope commenting on this video will be the equivalent of rubbing the buddha for good luck.
Michael Schiefer on the same boat as you bro.
Same, good luck all, and go to bed! Lol I was on my way but wanted to review this before I went to sleep b/c sleep solidify memories.
Yea good luck to you as well Jessica Hart
+Michael Schiefer haha same...the only time we need RUclips is the day before our exmas
+Michael Schiefer screw rubbing, clean the statue for more luck
My chi square results was 6.084. Since the degree of freedom is 1, the critical value under the 0.05 column is 3.841. Since 6.084 is larger than 3.841, the null hypotheses is rejected. There is relationship between the variables in the hypotheses.
I got the same answer!
I am same too
Crazy that I had to go on youtube to learn something that my teacher failed to teach for the past two weeks. Thanks a bunch!
I am a one of those students that has to learn on RUclips. Thank you for having done these videos you are saving my brain from a slow and painful death. This bio Golden Bear sure appreciates you. It is difficult not being at the university to have someone explain in person. You rock! I hope that only good things come your way. I was feeling stupid over this, but then I came upon your video and realized I have done this in my anthropology classes. My brain feels 1000x's smarter. Thanks to you
Started skipping my stats class because I was frustrated with the teacher, I just wasn't understanding it the way she was teaching it. He literally just perfectly explained in 11 minutes what took her 3 weeks to do and I actually understood it.
i got 6.084 so i failed to reject the null hypothesis , thank you i love your teaching
6 years and here i am using this comment for an answer on a genetics lab quiz
I first heard about Chi Squared in 1987.. As an undergraduate. It took you 11 minutes to teach me what
I couldn't grasp in 27 years! Bravo to you .. I want a refund for my tuition fees
Today was my first day of AP Bio and my teacher assigned us to watch this video and take notes. The answer to the pill bugs question at the end is no, we can accept but REJECT the fact that there is a difference between what was expected and what was observed.
The degree of freedom is 1 since there are two outcomes (and 2-1 is 1 according to the steps to determine the degree of freedom in an experiment). Then, when you write out the formulas and add them together, you get 6.084 as your chi-value. Since the degree of freedom is 1, you would have to look at 3.841 under the 0.05 column. Since 6.084 is greater than this number, we must reject the null hypothesis.
Cannot* accept, but REJECT
ily for the pillbugs answer
correct
thanks dude
My AP test is tomorrow and I knew essentially all I needed to know about AP Bio except for Chi-Squared tests, but thanks to you I actually get it. So thank you for saving my life.
You're a good teacher. Very helpful with my studies.
Ishrafa Ulianov For sure, this came in handy last semester. Good luck with your studies and coursework.
G. Reid I
you are my lifeline kind sir, my worksheet and textbook combined looked SO threatening, turns out its this simple. my entire education is built upon the foundation of RUclips channels like yours 🙏🙏🙏
I got 6.048 with 1 degree of freedom and 5% critical value, so, I rejected the null hypothesis.
Anybody else get the same?
I think you wrote the decimals in the wrong places. I got 6.084.
Boone Jones Maybe I'm missing something here, but that's the exact answer my calculator said
Yep, I got the same result, we reject the hypothesis
I got the same result!
I got 6.084.
I'm a school kid who struggles with maths. I study biology however and finally understand this and did the problem the end. Thank you Paul and people in the comments who I checked my answer with!
Did he just say "accept or reject?" Kids, you NEVER accept anything in staristics. Fail to reject
em kay oh in biology you say accept or reject or they graders wont count it.
+AllGoodsGee In statistics we're taught to say fail to reject because that doesn't necessarily mean we're accepting the null hypothesis. I think the entire argument is tailored around the whole "causation does not imply correlation" idea
other way around?
no
not other way around, you can never be sure of something being true, but you can be sure of something being false.
Truly this man is my actual AP Bio teacher. My real one doesn't know how to teach and just recites the exact words out of the textbook. I thank god for having this man to guide me through such a hard class
i love how you lower your voice when you're counting or doing calculation in your head!! Thanks for the videos! :)
The clearest explanation I have seen on Chi Square. At work I use it to insure the uptake probe is working properly. I finally have a clear understanding of the significance of our daily test. Thank YOu.
I am doing genetics at UMB and this was so much helpful and it made so much sense thanks so much for your help sir
I wasted over a week trying to understand this. And you explained everything in like 10 minutes.
Mr. Andersone you really make my life easier. Thx a lot
10.647
With the degrees of freedom being 1 and the point of significance being 0.05
The independent variable does have an effect on the dependent variable
Who else here for preppin for ap bio exam?
+Chretien li Not me, I am preping for Medical Biostat hypothesis testing!
right here
+Chretien li Yup! Me.
+Chretien li I'm for finance here :)
I have an ib bio test tomorrow
Statistics exam in 4 days and I feel like I know nothing. None of my lectures were clear and the whole class are scared. Thank you for uploading these. They may actually make the difference between me becoming a psychologist or not. SO grateful
u a psychologist yet?
Great explanation on the chi-square. Everything was detail and comprehensive.
What a way to explain Chi-square. Very simple and easy for anyone to understand ..
It is very important that you never accept a null hypothesis but rather you fail to reject it. I am in Ap statistics and I have have been taught that is a big no-no. They mean basically the same thing but accepting the null might indicate causation.
My AP Bio teacher sucks at explaining this that he just gave up half way and told us to go home and watch this. I'm so glad I have this!! Thank you!!
I got Chi squared = 6.084. And since we have only 2 options, so the degree of freedom = 1. For a critical value of 3.841 (i.e. 0.05 accuracy column), hence, the null hypothesis is rejected in this case!
I am a Biology and Chemistry major and get almost everything but some things, the professors have trouble explaining or go through it way too fast or the book makes it more complicated than what it is and then i come to you and everything makes so much sense!! You are amazing, thank you for being smart and helping me for the past 4 years
For Chi Square, I got 6.084. This is greater than 3.841, so I must reject the null hypothesis. Thank You Mr. Anderson!
Yes, the chi-square value is 6.084 and it is greater than the 3.841 rejection value at .05. Therefore, we can say that our observed data fails the test. Another way of saying it is that the null hypothesis fails.
yep, got the same result
This has probably been said a thousand times before but I can't thank you enough for making this so simple and easy to understand
I want to thank you for uploading this video. It helped me so much during my finals week.
Thank God. I am so happy this video exists. The text book just wasn't cutting it. Thank you!!
AP Bio Test in an hour, this literally saved muh life.
That makes me correct
your gifted with the ability to teach well and connect to any student far from you, i cant imagine what happens when they're near... many thanks
here's to everyone who has to take the bio exam online tomorrow..
zoe today 😂😂
Yes sir!
Lmaoooo
Ah I have an hour 😂😂
@@lizbethlozano1633 fuck samee
Got this video linked by a friend in preparation for my math exam at uni and holy shit, this helped me understand the test so much better than how my professor did it. The way he explained it made no sense and yours I understood by watching it once despite English not being my primary language nor the language of my classes.
Thank you so much! You are wonderful at explaining!
Thanks, I really needed this. I completely forgot how to do Chi Square and I have a Biology quiz tomorrow :) For that last one on Animal Behavior I got 6.084 and I rejected my null hypothesis because I think the Degree of Freedom (1) has a Critical Value of 3.841 in the 95% column. ^_^
Same! did you pass your biology quiz?
@@StarnochI hope they remember from 9 years ago
@@Laurzurelmfao🤣🤣🤣🤣🤣🤣🤣
Revisiting this channel after I first did in 2019. This particular lesson helped me obtained A+ in my statistic exam in L200 and I am back here to say thank you
happy AP Bio test tomorrow
thank you so much I hope you understand how many students you’re saving and helping
Nooooooo, 30 is for central limit theorem to suggest that the sampling distribution is normal, this is a chi-square test, you should look for at least 5 expected counts for each observation :(((
Brilliantly explained...It's all coming back to me from years ago at school. Thanks for choosing simple examples of flipping a coin and rolling dice; then building on that. Most videos start with complicated research hypotheses, which may be largely irrelevant to people interested in pure probability and chance.
My chi squared value is 6.084, we reject the hypothesis
Awesome this person deserves golden credit for simplifying the chi square.
let me get a 3 or 4 on this apbio exam pls
(hopefully this comment will serve for good luck)
update: I GOT A 3 GUYS. also tfw chi square wasn't even on this dang test
chriseria nice lol
watching this the day before the exam because I haven't understood it the whole year
This is immensely helpful, even for me (I'm an IB student). Thank you!
you just made a confusing hour and a half lecture make sense to me in 12 minutes. Thank you!
Thanks so much my final's tomorrow and I finally get how to do these!!
I have a test today and I watched this guy’s videos to help explain. Let’s hope I don’t fail!!
Wow, thank you soooooo much! I was trying to figure out what my textbook was saying, however it was totally a waste of time, how could I understand without any examples or even graphs on my textbook? You made it easy for me! Good job, and thank you a lot!
I just discovered you. Thank you so much for your clarity. I owe you the blood of my first-born. 🙏🏽
not all heros where capes
+Darwin Phillips wear
I've failed my Statistics class once, second time going now, 2 Lecturers have attempted teaching me Chi Squares.. well not blaming their methods, but finally I understood this! Thank you good sir!!
null hypothesis rejected because the critical value is 3.841 and the chi-squared value is 6.084. there is a significant difference between pill bugs spending time in wet versus dry places
My teacher just sped through chi squared as a whole just to spite me bc I joined AP bio...He didn't want me to but I did anyways so I came here to actually learn it. It really helped and I got a 6.084 so deny that using the null hypothesis
80 people rejected the null hypothesis
statistically insignificant
This is what my teacher was teaching for a whole week and i couldn't quite get it....thank you so much
_Here is the answer with steps to how to do it if any of y'all need it from the future, past, or present!_
Wet + Dry
Xctotal^2 = Xc^2Wet + Xc^2Dry
Xc^2= [ (Oi-Ei)^2/ Ei ] + [ (Oi-Ei)^2/ Ei ]
Xc^2= [ (8.9-5)^2 / 5 ] + [ (1.1-5)^2 / 5 ]
Xc^2= ( 15.21 / 5 ) + ( 15.21 / 5 )
Xc^2= 30.42 / 5
Xc^2= 6.084
Degrees of Freedom = (N1+N2)- 1 = 2-1 = 1.
Critical Value = 0.05
Final chart value = 3.841
*_6.084 is greater than 3.841_*
*_Hence the Null value is rejected._*
_You're Welcome._ 😊👌
Thank You! This helped me figure out what I did wrong
Your teaching still helping students after 8 year... well thanks a lot.
i knew how to do Chi-Square, but didn't know why...
Remember you do not "Accept" the null, you "Do not Reject" the null.
Mr. Anderson, you are wonderful and have made learning the chi-squared test simple indeed!!! Thank you so much!!!
so whats the answer? Cause I got my chi square value to be 6.084, degree of freedom to be 1 and using critical value of .05 I ended up rejecting the null hypothesis
i got the same answer
Why did u use the degree of freedom 1... The expected value is 5 thus 5-1 is 4 this mean u use 4 as ur degree of freedom
Fuad David Actually, there are only two outcomes: wet or dry. 2 - 1 is 1, so you use the first degree of freedom. The expected values don't matter when figuring that part.
thanks brother
'Course bro
ERROR IN THE CHI-SQUARE ANALYSIS?
I love Mr. Anderson’s videos and frequently recommend them to my students and fellow teachers. As a first year AP Biology teacher, I have relied heavily on his help for explaining the labs that we have done. However when my students did the pill bug experiment, we didn’t get results that were as clear cut in giving a chi-square critical value that allowed us to reject the null hypothesis. We went back to the lab and gathered more data and still had the same problem. It looked like there was a difference but the chi-square critical value was still below the threshold for rejecting the null hypothesis, so I began to examine the analysis.
I don’t have a good background in statistics so I went to a publication by BioInteractive, on the HHMI.org site, Mathematics and Statistics in Biology, written by Paul Strode, PhD, and Ann Brokaw. A statement for p.21 caught my eye, “Note that this test must be used on raw categorical data. Values need to be simple counts, not percentages or proportions. The size of the sample is an important aspect of the chi-square test-it is more difficult to detect a statistically significant difference between experimental and observed results in a small sample than in a large sample.” www.hhmi.org/biointeractive/teacher-guide-math-and-statistics
By adding up the columns (excluding the first data points at time =0) instead of taking the average, we get chi-square value of 73.96. This is extreme in this case, as the preference of the pill bugs is very clear, but using the raw data allows us to reject the null hypothesis in much less obvious sets of data.
This also helps illustrate the debate in the comments here about “accepting” vs. “not rejecting” the null hypothesis. If the chi-square value is below the critical value, we may “not reject the null hypothesis;” however, we cannot accept it either because, as was the case in my classes, collecting more data which reflects a small difference becomes significant once the data pool becomes large enough. This is my understanding of the real value of the chi-square test in telling us when we have found a significant difference in results.
Awww, am I the only one who finds it adorable he got his wife involved in the video? ^o^
..probably.
are you still alive
@@Eomionis.Vow. LMFAOOO
THANK YOU YOU'RE A SAVIOR!!!!!!! i go to an all-girls school in upstate NY and we all watch your videos.
#BasedBozeman for AP BIO EXAM!
You're a saint. We need more people in the world like you. Free education for all.
What if the coin stands up XD
You make a meme
Zihao Qi Technically not impossible but very unlikely
Great explanation! Lecture was 2 hours long and you did it all in a 12 mins video! Saved me from watching a 2 hours long lecture recapture.. thanks a a lot for all the effort!
technically you would Fail to Reject the Null Hypothesis according to statistics, you never want to say you Accept it
I love how you make the materials seem very simple. Than you.
For the last problem I gt 6.084 so I reject the null hypothesis. Thanks for the help(:
yep me too :D
Honestly can this man just be my teacher. Such good vibes thank you!
What do you do if your chi square value is also your critical value?
Then you still have to accept the null hyp. since u are on your "limit" of sureness (0.05 in this case)
Which one is true then?!If the chi square is equal with the criteria value
Cry... Actually this just means your data is right on the cusp of being considered skewed by a variable. So it COULD be chance (technically it can always be chance) but it's fairly unlikely
In science, we typically want to be on the sure side of things. If your data happens to be right on the critical value, you'd probably want to take more data. Or, you can simply report that your data had a p-value of 5%.
You reject your null hypothesis because you are 95% sure that the data value is less than the critical value, and 94.99999% for anything equal to or above it
For pill bugs, the chi-square is 6.084 using the data, and since there is 1 degree of freedom (2 different variations MINUS one) and the critical value for that degree of freedom is 6.314 in the 0.05 column, the chi-sq is less than the critical so you must ACCEPT the null hypothesis (and you know there isn't any outside force that affected your data and there isn't a large difference between your expected and observed data.
so my bio teacher said that saying "accept" the hypothesis is not really good, we should say "faill to reject" the hypothesis, which one should I use?
Mr. Anderson = Angel of wisdom.
Oh dang this is actually quite simple! Thanks again mr. Anderson!
Over the past 12 weeks in my bio lab I've been copying other peoples work because I didn't understand this, now it makes perfect sense to me. Taking my final today and I should have no problem with these questions.
Chi Square = 6.084 | degree of freedom was 1 so the critical value = 3.84 and there for its evident that there was a significant difference between our expected and observed values. Hence.... something was definitely causing those bugs to prefer the wet environment! wooot!
How exactly do you calculate degree of freedom? Number of outcomes - 1?
Cognitive Philosophy yeah basically
+Cognitive Philosophy or you can say it is the difference of sample space - 1
if u thrown a dice to get one outcome(in 1,2,3,4,5,6) except that it has chance of five another outcomes, so for the dice DOF=5
It's the number of possible outcomes minus 1 to obtain the degreees of freedom.
God bless you!!! I have a bio final tomorrow and this is the one thing I didn't understand!!! This one video explained everything!!!
did you just ACCEPT H0 ??????
thought the same :D
Mr. Anderson, I first saw you my sophomore year of high school for AP Bio help, now as a college junior I was so happy to see this video pop up for a refresher stats lesson
anyone is struggling before 2020 ap bio exam
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omg this man is literally teaching me more than my actual teacher. he's the whole reason im gonna pass this course😭😭
Chi Square value is 6.084 and our critical chi square value is 3.84. Since the chi square value is more than critical value, there is a significant difference in Animals spending time in wet and dry places. Am I correct?
+Shahrier Rafiq yes
+Siddu Kolli I have a question. In my book it says on the Chi Square table that: The calculated value must be equal to or less than the critical value for significance to be shown. If 'significance' means 'difference' and 'Difference' means 'rejecting' the null hypothesis, Why is it that 6.084 which is higher than 3.841 rejecting the null? Isn't it supposed to be accepting it, since the calculated value is higher? *confused.
+Random Leaner 3.841 is the critical value when the degree of freedom equals one. With the pill bug data the actual degree of freedom is 10-1=9 (10 being the number of pill bugs). On the chart, the critical value point would then be on row 9 under .05 which is 16.919. This makes it less then Chi-Square value which makes us accept the null hypothesis.
so the correct answer is to accept the null hypothesis right? because the degree of freedom should be 10-1. i almost got confused looking at some other answers, thinking we had to consider wet/dry as i was wondering how they got their critical value as 3.841
+Jess Lee Remember that there are only 2 outcomes. So degree of freedom would be 1. Also, the null hypothesis for Chi Square tests is that there is no difference. So we reject the null if the obtained chi square statistic is above the critical chi square statistic
You are one of the best teacher I ever had , thank man , you can make everything simple
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you're my hero!!!!! keep doing what you're doing, teach us better than our own teachers and continue to inspire young Minds.