Statistics 101: Single Sample Hypothesis Z-test Alpha and p-values
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- Опубликовано: 9 сен 2024
- Statistics 101: Single Sample Hypothesis z-test - Part 3
Part 1: Conceptual Background
Part 2: Example Problems
Part 3: The Alpha Effect and p-values
In Part 3 of this video, we examine the relationship between the alpha level (significance level) and the critical values of the rejection/nonrejection boundary. What happens to the critical value when alpha is changed? Additionally, we talk about how Type I and Type II error is affected by this relationship. Finally, we learn how to find the precise p-value for the hypothesis test: the exact probability between the z-statistic and the tail(s) of the distribution. This is usually referred to as the observed significance level.
Remember for this type of test we are comparing a sample mean to a hypothesized population mean. We examine the rejection region, nonrejection region, and the critical values that separate them. Enjoy!
My playlist table of contents, Video Companion Guide PDF documents, and file downloads can be found on my website: www.bcfoltz.com
Brandon has done an excellent series of videos for people who want to learn statistics from scratch. It assumes a fairly low level of prerequisite Math ability. If you are more advanced, you can skip or scan certain parts of the videos and go for the innumerable gems. The gems shine light on key concepts and pitfalls in understanding. Thanks Brandon for helping me, a 69-year old retiree, learn statistics. I deeply admire your tremendous efforts and perseverance in producing these hundreds of videos. Wonderful ❣️
Hi Brandon,
I haven't studied statistics thoroughly ever before. I am grateful to have come across your videos. They are easy to follow and do not miss anything at the same time.
The examples in each topic makes it to be able to relate to a real life problem.
Thank you.
I found you last week. The exam is in two days. Its a compressed, seven week semester. The instructor wouldn't even answer my question when I asked him for the definition of a p-value. Ohio State.
They got half the course farmed out to MacMillan publishing. The book suffers from poor editing and vagueness. The instructor is abysmal. I started finding success with Khan academy but there are week areas there. I have put in scads of hours.
You are very very very good. You are a life saver. And you have a clear and soothing voice which is a major plus for my frayed nerves.
THANK YOU!!!
I want to avoid hyperbole, but this lecture series is a true masterpiece of education. If B.F. disappeared from the internet tomorrow (hopefully he won't), this series would endure long after. It is an achievement of immense work, organization, and directed energy. There is far too much to list, but one feels the guiding yet unobtrusive hand of a true master in these videos.
Thanks Brendon. I have looked at a lot of material which was nowhere near your simple and excellently designed lesson plans and plenaries. Keep going, your work is invaluable to many.
I am a statistics teacher. Thank you for your efforts making these videos. I will be using them in my classes and share with my student.
this playlist has saved my life! thank you so much!!
The entire playlist has been stellar, but this video was just -- MONEY!! Absolutely wonderful job!
I have been following this series of statistics video to clarify certain doubts related to my other Data Science course, I must say, Its amazing teaching ability, its content, pace , clarity and the flow ..outstanding !!!
Sir, you are a true legend! I am preparing for my stats exam and your videos are really helpful. I have no words to thank you. I wish your service reaches millions of deserving students!
Thanks so much for the help! Your step by step instruction ( and being able to pause to write notes and check Z table) has made this seem as simple as.. just following steps. Your kind words in understanding the struggle to comprehend are also uplifting.
Our course is using a Z table with numbers representing the percentage of scores that fall between the Z score and the mean ( z=1.96 shows a percentage of .4750).I have no clue how to use it. ( I guess I have to subtract from 50 and then multiply by 2) I finally had to find other tables to follow your videos.
Thanks Again!
I love how you speak slow giving me plenty time to think and catch up with what you're saying. Thank you so much for helpful videos!! :)
You really helped me and saved a lot of time that I should have spent to understand these concepts... Thanks a lot.
Just perfect. Thank you so much.
For viewers; patiently watch all thee parts and then think about your questions.
This cleared up a lot of questionmarks during my statistics course! Thank you!
Very well done. Much appreciated and very useful. Great graphics. Excellent articulation. The video presentation method is superior to the classroom because it can be paused for note taking or other needs. MUCH better than the book because math is a procedure, not a concept, thus like any actual process, it must be observed and practiced to be learned.
Hi Brandon
I just wanted to say thank u for your playlists. They have really helped me during these online learning and pandemic times🤞🤞.
videos are amazing. these things are actually quite easy thanks to you. i guess passing the knowledge to another is a skill. good job
Everything is so well explained ...Great job .
looking forward for more of yours videos which would help me learn better .. thank you .
i love how you encourage at the beginning and end of the videos :)
great work! ure a pro!
excellent explanation. only suggestion is...include more examples....
God bless you 💘, for making such easy to understand statistic videos, I have always called statistic "sadistic" because it causes me so much pain lol thank you again
Hahaha😂
hell yeah thank you dude
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thank you .. a nice comparison of alpha ...
From the tables Area to the lift of Z in case of 2.5 is 0.9938, 0.0062 for -2.5
Please advise
Hi Brandon. These videos have been a lifesaver for me as a more visual/lecture learner. Why are the z values different theoretically when there is a one tail test than a two tail test?
Thanksssss so muchhhhhhhh
My only suggestion has nothing to do with the content. I am finding it very confusing (in many of your videos) to find the 'part 1' and 'part 2' videos. You don't have 'part xx' in your title so I am never sure if I'm watching the second half of the first video or some other video completely. A clear naming convention would be a huge help.
Hi Brian! I actually have all the videos organized into nice, neat playlists. The thumbnails also have the playlist and video number. You can also find the playlists here: wp.me/P1TVs6-1R Thanks for watching my friend! Keep on learning. 🙃
Hi Brandon. Quick question. I get how to derive both the z-score/critical value and the p-value. But after watching this video, and knowing they both lead to the same conclusion, when do you use which method? What's the point of using the p value method; and how is it different from using the z-test? Thank you in advance! And please keep making these videos. You have a gift for explaining complex concepts well:)
Hello! p-value is usually the way to go for the end result because we express hypothesis conclusions as compared to our alpha level, 0.01, 0.05, 0.10, etc.
@@BrandonFoltz Oh I see! Thank you!!
Great video once again!
Great videos! Thank you so much! :)
Beautiful work as I said earlier. I have one little question though.
How do I calculate p values for ANOVA one way and two way test?
Do we need to use interpolation at any point? If so what are my references?
Thanks Brendon！
Thanks for this video. What does the p-value exactly mean?
For Example:
If we get p=0.18 & Alpha=0.05 We fail to reject the Null,
what does that 18% or 0.18 mean?
Please clarify me.
Hi, I would like to ask why the P-value in this video is greater than α, and then we can reject H0; however, in the other video, the P-value is less than α and we also reject H0? Thank you to explain.
Brandon, are you going to do any on Method of Moment estimates or/and maximum Likelihood estimates?
Just a quick question. Why is the observed significance level only the part to the right of our test statistic of z = 2.5 ? Why does it not also include the area between our critical z = 2.33 and the z = 2.55 ?
Sorry Lex Gabrees, it is not the observed significance, it is the observed probability of rarer events (greater values), so we consider the right to our point of interest 2.5 and compare it with the right to our critical value of test statistic, here its z=2.33 and conclude whether or not, my value is greater than cut off value for the mentioned significance level. Naturally, you can also observe that the area under the curve decreases with increase in the z score, so p-value should be less than the significant p-value to reject your null hypothesis
0 dislikes, because how could you.
amazing
I would like to know more about p-value, can you help me?
Hi Brandon, 9:50 minutes into this video you started discussing p values. For the life of me I cannot find .0062 in the z table. Please explain how you came up with a p value of .0062 from a z value of 2.5. Thank you.
The Z-table gives the area to the LEFT of the z value. If you look at the Z-table, it will give a p-value of 0.9938. However, in the Starbucks example, we are looking for the area to the RIGHT of the z value, which we get by:
1-0.9938 = 0.0062
Hope that helps! :)
Hi John, it does! Thank you!!!
John, can I ask another question? How do I find p if the only thing I am given is u, a range of x out of y, and the degree of confidence?
@@johnshepherd2011 Hi John, Thanks for your answer. I just need one more clarification that in Z-Table you took Z=2.5 @ a=0.00, however a=0.01 so if we take at a=0.01 then it could be 0.9940 rather than 0.9938? your advise please
Thanks!
great
In the previous video when alpha =0.05 z=1.96 but in this video z is 1.6, is this an error?
Hi,
Z-crit = 1.96 when alpha= 0.05 for a two-tailed test
Z-crit = 1.645 when alpha= 0.05 for a one-tailed test( here the example of starbucks is used)
Hope this helps.
Around 0'48", alpha equals 0.05, the z- test critical value should be 1.96, right? Where's the 1.645 from? Whoever answer this, thanks in advance :)
On his previous video on the playlist he was doing this example problem which had a one-tailed test. Hence with alpha = 0.05 on a one-tailed test the critical value is 1.645 instead of 1.96 which is on the two-tailed test! :)
XIE XIE！