Hypothesis Testing Problems - Z Test & T Statistics - One & Two Tailed Tests 2
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- Опубликовано: 29 сен 2024
- This statistics video tutorial provides practice problems on hypothesis testing. It explains how to tell if you should accept or reject the null hypothesis. It gives two examples - one involving the z-test and the other involving the t-test or t-statistic. One of those examples include a one tailed test and the other contains an example of the two tailed test.
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Confidence Intervals & Margin of Error:
• How To Find The Z Scor...
Find The Z-Score Given Confidence Interval:
• How To Find The Z Scor...
Student's T-Distribution:
• Student's T Distributi...
Hypothesis Testing - Null & Alternative:
• Hypothesis Testing - N...
Type I and Type II Errors:
• How To Identify Type I...
One Tailed and Two Tailed Tests:
• One Tailed and Two Tai...
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Test Static For Means & Pop Proportions:
• Test Statistic For Mea...
Hypothesis Testing Problems:
• Hypothesis Testing Pro...
P-Value Method - Hypothesis Testing:
• P-Value Method For Hyp...
Hypothesis Testing - Proportions:
• Hypothesis Testing - S...
Difference of 2 Means - H Testing:
• Hypothesis Testing - D...
Cohen's D - Pooled Standard Deviation:
• How to find Cohen's D ...
Hypothesis Testing - 2 Proportions:
• Hypothesis Testing Wit...
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Matched or Paired Samples t-Test:
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Chi Square Test:
• Chi Square Test
Chi Square Distribution Test:
• Chi Square Distributio...
Test of Independence - Chi Square Dist:
• Test of Independence U...
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Helloo! Can you please make a video lecture of hypothesis testing using t test and z test again, but this time with managerial decisions? Thank you!
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0
If the mean is not equal to 2, it is a 2-third test, and if the mean is less than 2, it's a 1-third test. Can you please explain this better in the next video?
No cap, I learn more from this youtube page than my actual university lessons
As always. University is just a proof that you probably learn it not a means to actually learn something 😂
University Assigns, RUclips Teaches.
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Thank you i understand good job, and now I Know that 1.96 come from table distribution
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To those wondering on the Z-score values of 1.96 and confidence value of 95%:
Confidence level (CL) formula = 1 - (confidence value) = 1 - 0.95 = 0.05, and we divide this by 2 (0.05/2) to get the alpha values on both tails ~ 0.025.
You can also use this formula A = (1-CL)/2 which gives you your alpha for one tail. As these graphs are symmetric we put the alpha values on both sides.
Once you have this value you go on your Z-score table.
At alpha value = 0.025, look down at the (deg of freedom which is given by formula: 1 - n, where n is sample size) but since we have 1 - 40 = 39...
The 39 is no where on the freedom column. In this case we use the infinity value which is: 1.960 ~ 1.96
Cheers
This is my question, thank you so much
"The 39 is no where on the freedom column. In this case we use the infinity value which is: 1.960 ~ 1.96" Is this because it is a Z distribution? if its T should I just use the nearest degrees of freedom to the value of n-1?
@@los1868 same concept. If you do not find the deg of freedom that matches on your table then you can use the infinity value from the t distribution. (I am not a teacher sorry so I can't describe the story as to why but this is something I find works in every question that I have encountered so far.) Hope it helps!
Thank you man
do you mean the T table because in z score table there is no alpha or deg of freedom ?
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I just want to say that your videos go over the exact curriculum in classes I’ve take since high school and I almost have my degree now, I have probably watched your videos more that my lectures. I don’t know how you have this much skill and organization to put the videos out that you do, but ur a straight blessing to any student out there who needs help - u the best tutor ever
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If your reading this comment, thank you! You saved me from a big quiz in school and i didnt study for it but this video while riding the bus to school is a blessing. Got 55/60. THANK YOU!
Youre welcome
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Study next time, said the instructor..
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How did he get the 0.025??
Please enlighten mee
@@NONAME-yv3lq Its the leftover 5% from the 95% confidence level, split on each side to make 0.025 or 2.5%.
I've been watching him since sophomore year of high school and now I'm a junior in college and am graduating. It's wild how much this man has saved my grades since I was 16 lol
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Null hypothesis of life: life is painful because of those non departmental courses, which you can't reject
My university professor discussed this for 3hours, yet nothing came into my mind lmao😂 this 13mn discussion makes me feel smart y'all
well i guess, i should've just enrolled here in youtube instead of school since i still go to youtube to learn our lessons.
me literally watching this during my final exam
Thank you for taking your time and going through The Z and t procedures in a step-by-step manner in which I could understand understand. Furthermore I appreciate the way you compared the t critical value To the T test statistic using the formula which now helps me to understand how you reject or fail to reject the null hypothesis.
The alternative hypothesis is not rejected when the null hypothesis is rejected?
Help! Our professor taught us to determine whether to use z or t-test, we look at the SD!
Z-test = Population SD
T-Test = Sample SD
Did your prof teach you to determine it this way:
If population SD is known, use Z-test
If population SD is unknown, use T-test?
If yes, I'm having the same confusion as you
@@stephaniandrea5726 Mine did
@@stephaniandrea5726 if u unknow SD but ur sample is >30, u can use T-test ecuation to know Z value
This entire comment section...THANK YOU ❤️
@@killergames3634 why is it 30?
Thank you so much man. I'm having an exam in the next 5hrs
You really explained this well 😊
Another great video. Thanks a ton. My stats Professor is decent at explaining fundamentals but this really puts everything he’s said into context and practice.
You seriously saved me hours and hours worrying.
excuse me, may I know the reason why (N-1) formula is not used in calculating z-score?
As per the video, our condition for t test is sample size less than 30 and population std not known. However, population std was not known even in 1 scenario also.
But what role does population std plays here. Coz' in both the examples, we didn't needed to use population std..so why this factor is important
Coming here cause my university teacher makes me hate math, they explain it HORRIBLY
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I think the statement made at 5:00 is misleading. Since if we increase the confidence level to say 99.99 then the calculated z value will definitely fall between the region of acceptance. That means at 95 cl we reject the null hypo but at 99.99 we accept it. Please correct me if I m wrong.
My Lecturer used 2 weeks not capping …two weeks to explain this and I still didn’t get it..Watching this vid I understood in less than 13 mins
I feel so safe watching these videos like I am going to actual get information that is clear, concise & makes sense. I wish my professors understood that is far more important, then trying to impress me with jargon.
2:50 why 1.96 tho :(
Its from a z table that you have to refer to the confidence interval 0.95 refers to z value of 1.96 in the table
You didn’t explain how to get the critical values
The critical value is the normal distribution table value of the level of significants (1-the confidence interval) example--- (1-.99) = .01 look this value up in the normal distribution table.
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I read my module for almost 1 hour and I have a difficulty understanding it but in the first 5 mins of this video I already understand the lesson that I am studying. THANK YOU SO MUCH!
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why is the critical value 1.96 ?
Use z table
In a normal distribution curve 95% of the values lie between -1.96SD to 1.96SD. 99% of values lie between 2SD to 2 SD.
You take that 0.95, subtract it from 1, you get 0.05, divide it by 2, you get 0.025. Then you go to your z distribution table to look for 0.025, it's under 1.96
How did we get the 1.96?
ruclips.net/video/sJyZ9vRhP7o/видео.html
1.96 is the critical Z value. Actually calculating it is complicated and you usually aren't expected to know how or memorise them. You usually can just look it up. It's like the relative molecular masses of elements.
@@animanfan5442 where can I find it?
@@pamjarina8201 just search for Z/t values. It’s like searching the value of pi
PSA: the professor you get for Stats matters so much. I was scared of taking Stats, and now I've fully learned and enjoyed the class because my Prof is great, he's very helpful, well spoken, and hands on when helping us understand. A good teacher makes all the difference!! and asking tutors for help :) good luck y'all, you got this!
@abbieamavi can I show you a problem?
my professor sucks
Your videos on youtube are simply the best it has help me to validate all my Biochemistry courses. Thank you JG. I wish I could make videos like you just that I don't have the equipments 😁
Same, I think we should. It would help our fellow STEM colleagues so they won't get stuck on this and can instead use their minds to advance the fields and postulate new ideas. Any help would be useful
This guy’s lectures are very detailed while my professor’s lectures are too abstract. Thank you so much for helping me out!
for the first question, since the sd was from the sample of 40, shouldnt we find the unbiased estimate of the sample variance first ?
Thanks I was confused because I was using the Zc value for the critical region instead of the z table value..I'm clear now
can somebody tell me where 1.96 came from in the first example pls
He got another video about finding the z-score in his channel
Search and you’ll find it.
I was wondering the same thing...did you ever figure it out?
I really don't get why lectures that are 50 mins, 60mins sometimes 2 hrs are that long when I learn the same amount, definitely more content in a 13 minute video made by OCT than any uni lecture out there. Just goes to show, they set aside a "time" and its just filled with useless shit most of the time. Here, you learn everything you need to in this short time. In uni? content finishes 30 mins early and the next 30 or so minutes is wasted with useless info or dragging out the class.
Makes so much sense! This week in my MATH302 course we’re going over hypothesis testing for sample T-Test, sample Proportion, 2 Proportions, 2 independent samples, paired samples.
Bro thank you, i was visibly confused at this lesson plus we had a formulated test to do, so i panicked until i watched this video 😅
Rare gem. Thanks a lot for all your explanations.
In Q1 Why would you ue a Z test when you don't know the population SD? You also used the t-test formula, not the Z formula (z=X-mu/sigma)
Because the sample size is 40 > 30 so must use the Z-test with Large sample size
you can use the T test considering the DF is infinite and you will get the same answer.
Thank you so much!! keep doing what you do. You are an excellent teacher.
Anyone tell if I have population Standard deviation but n is less than 30 which test I should do?
Thank you!! This topic was giving me soo many problems and I couldn't understand it from my teacher for the life of me! But this cleared me right up, I even have an exam on this topic today and now I feel prepared rather that stressed, thanks!!
Wow our lecturer gives the video to which. She said that it is batter than her explanation 😮
Thank you for this video..i really learn a lot..hope to see more videos from you..Godbless
where can we get the 0.025 and 1.96? i still dont understand pls help me i have this material for statistic exam tmrrw
Man....where were you went I was struggling with stats! I learned more in this video than I did during a whole term at school. Awesome work. Thank you.
Thank you, man. Exactly this question was given as the take home test and I get done within few minutes after watching.
The "organic chemistry" teacher teaches better "math" than my math teacher xD
Amazing stuff... u r a life saver. I have actually grasped the dreaded Hyp. testing in full now. Awesome!!!
hello sir, do you have videos about false positive and false negative? I'm dealing with questions like this but i couldnt find any videos about it:
A supermarket suspects one of their production machines is incorrectly filling bags of flour. The expected mean weight is 1.05 kg with a standard deviation of 20 g (to avoid under-weighted bags). What is the minimum number of observations required to detect a deviation from the expected mean of more than 10 g, with a false-positive rate of 10%, and a false-negative rate of 20%? Assume that the observations are normally distributed.
thanks!
In fact I was so confused after my lecturer rushed me through this but now I have gained freedom from this lessons, God bless you so much Prof ❤️
this may sound like a stupid question but where did you get the 1.96 from? im referring to example no. 1, 95% or .95
The Z score, referred in standard normal distribution conversion table for the Area under the curve which in video is p= (0.025) --> Z = ±1.96
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Your lessons managed to get me 84% for a test, where would I be with out your videos
omg thank you so much. I was so confused about how the t-test and rejection/accepting the null hypothesis worked together. I've been so confused about all of this for like 3 years (yes I procrastinated that much). It should really help me pass my statistics test for biochem. working the way through example was a really good way of explaining it.
from where does that 1.96 value comes?....
You literally explain in the best way for dummies, I swear! A lifesaver.
Better than your Marxist professors? Who would of thought.
how do i knoow if there is enough evidnce ?
please help me
I'm currently preparing for the CFA exam. You clearly and easily explained this material in under 14 minutes whereas my study guide devotes a 20- page chapter. THANK YOU!!
Agreed. Used for my CFA, by far a much clearer explanation
Ah, hello there, fellow CFA folks. This man does make hypothesis testing much easier!
Thank you !
I never understood the one and two tailed test before and watching this video will help me with my biostatistics class.!
Where did you get the 1.96
That's my wonder too
Normal Distribution Tables, You do Area Left = (1 + cl )/2 then you at what exactly that area corresponds to as a Z value.
Mehn.... this guy you are literally an academic saver......there is nothing that I don't get to understand after watching your videos. Thanks a million!!!!!
in the problem no. 2, it is a left tailed test therefore if it is 0.99 confidence, its alpha is 0.005 not 0.01, because 0.01 is for two tailed test only.
no it would be 0.005 for 2 tailed test because u have 0.01 split over 2 zones, right and left
@@SirGrizzlyman exactly
He's actually right but alpha is 0.01 but alpha/2 is 0.05 one tail should be used so 3.250 not 2.82
lmaooo I have an exam today that I havent prepared for, but this man is making me feel like I will actually pass, best education account fr, way better than proper university lessons. Should be paying my fees to this guy.
Did you pass?
I've watched videos that teach the t-test but this video explained the purpose and calculations more masterfully. Thank you.
omg you are going to be a millionaire if each student understood sent a dollar, you are a stat prophet !
THANK YOU SO MUCH. Seeing these brilliantly simple to understand examples is really helpful for me to conceptulize the topic
bro 2 lectures and two tutorials, 8 hours and this guy made me understand better in 13 mins
Your videos on youtube are simply the best it has help me to validate all my Biochemistry courses. Thank you JG. I wish I could make videos like you just that I don't have the equipment thank you so much brother
could you please make a video on anova? I'm getting so much help from your videos! thankyou so much! you're the best teacher
wow,i was to compalain about the values of 1.96,but then i have realised,patience was being tested on my side.Thanks sir for your wonderful approach
This video seriously SERIOUSLY helped, between yours & Maths & Science tutor’s channel, you guys are teaching me stats from the ground up! 💯
I STILL CAN'T UNDERSTAND SINCE MY TC GAVE US DIFFERENT FORMULA OWHDISJSIW I'M F UP!
We'll take our exam on Statistics a few hours from now and your video is a big help for me to answer my exam. Thank you!
I didn't understand can you help me
foe the second why is the value 0.01? should it not be 0.005 ?
I thought so too. Shouldn't it be 0.05? 1-alpha / 2?
Legends watching this video before one day of exam🤣
On the day of exam😊
You seem like you know your stuff, the thing he doesn't cover the other two examples, the t distribution table with 2 tails and z distribution with 1 tail. is it the same thing or is there a difference in the calculation. If we are doing a 1 tailed with above 30 for sample size, we need to use the z score. If i have 92% CI, then my alpha is is 0.08. So then the area covers is the same as my CI which 0.92. I go and get the z score for the 0.92 and set that as my critical number. Use the formula of X(bar) - mu(sample average)/SD/sqrt(10) and compare?
leaving a comment
This makes me crystal clear on null and alternative hypothesis testing.... Thank you so much for this video
You just saved my butt on this exam dude
Nicely explained thank you very much. I learn a lot from this video. keep doing these types of vides.
👋😀
The first question is not correct. The formula should use population SD. Since no population SD proceed t-test.... Based on my research 1-2 hours and ChatGPT