Chi-squared Test
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- เผยแพร่เมื่อ 12 พ.ย. 2011
- Paul Andersen shows you how to calculate the ch-squared value to test your null hypothesis. He explains the importance of the critical value and defines the degrees of freedom. He also leaves you with a problem related to the animal behavior lab. This analysis is required in the AP Biology classroom.
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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!
🥇🏆🙏
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
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 👍
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.
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 TH-cam.
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!
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
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 TH-cam is the day before our exmas
+Michael Schiefer screw rubbing, clean the statue for more luck
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??
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
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 TH-cam. 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
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.
i got 6.084 so i failed to reject the null hypothesis , thank you i love your teaching
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
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
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
Great explanation on the chi-square. Everything was detail and comprehensive.
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.
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
I want to thank you for uploading this video. It helped me so much during my finals week.
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.
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'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!
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
Mr. Andersone you really make my life easier. Thx a lot
quick short video, but very effective. please keep doing what you do. you're saving lives over here sir
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
i love how you lower your voice when you're counting or doing calculation in your head!! Thanks for the videos! :)
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
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 TH-cam channels like yours 🙏🙏🙏
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 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 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!
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!!
Mr. Anderson, you are wonderful and have made learning the chi-squared test simple indeed!!! Thank you so much!!!
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.
AP Bio Test in an hour, this literally saved muh life.
That makes me correct
Amazing explanation skills, I learned t-test as well from another video. I wish our teachers were as simple and clear like you. Thanks and keep doing great work.
You have the best explanations out there! If only our lectures/labs would teach us this way. :( Thank you so much, Mr. Anderson!!
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
This is immensely helpful, even for me (I'm an IB student). Thank you!
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!
you just made a confusing hour and a half lecture make sense to me in 12 minutes. Thank you!
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!
Thanks so much my final's tomorrow and I finally get how to do these!!
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
I just discovered you. Thank you so much for your clarity. I owe you the blood of my first-born. 🙏🏽
My chi squared value is 6.084, we reject the hypothesis
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
Thank you!! You're saving my life with your videos! Wouldn't pass my big exam without these videos :)
You are a legend! Taught me in 11 mins what my paper couldn't teach me over a semester.
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🤣🤣🤣🤣🤣🤣🤣
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 :(((
Thank God. I am so happy this video exists. The text book just wasn't cutting it. Thank 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.
Oh dang this is actually quite simple! Thanks again mr. Anderson!
not all heros where capes
+Darwin Phillips wear
You explain very well, the hallmark of a great teacher. 👍
This is the best and comprehensible lecture for my stats class! Thank you so much 🙏🏼
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?
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
You simplified a subject that has been so baffling! Thanks so much
thank you so much I hope you understand how many students you’re saving and helping
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
80 people rejected the null hypothesis
statistically insignificant
Thank you!! I liked being able to use your exampled to further my understanding of the Chi Squared test. I actually corrected a mistaken assumption I had about the formula, so I can honestly say that I learned something
THANK YOU- I have a bio lab final tomorrow and you saved me. This was the only good video I could find on chi square and looking at the chart to interpret it.
happy AP Bio test tomorrow
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
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?
I love how you make the materials seem very simple. Than you.
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
Remember you do not "Accept" the null, you "Do not Reject" the null.
Thank you Mr Anderson. You really have made everything easier!
Thank you! Keep on doing what you do! Youre helping a LOT of people!
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
What if the coin stands up XD
You make a meme
Zihao Qi Technically not impossible but very unlikely
Thank you so much for this video! You break it down so well and make it so easy to follow.
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!
anyone is struggling before 2020 ap bio exam
Sydney Tze starts in 7 minutes
Alexander Alekhine great I’m gonna fail
did you just ACCEPT H0 ??????
thought the same :D
You are one of the best teacher I ever had , thank man , you can make everything simple
Honestly can this man just be my teacher. Such good vibes thank you!
#BasedBozeman for AP BIO EXAM!
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.
That simple way of teaching is awesome man ..... thanks a lot
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
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)
Luis Alexis no.....
if your Chi squared value is greater than or equal to your critical value then you reject the null hypothesis.
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%.
can I apply this critical value table on any of my hypothesis analysis? is this the standard scale? thank you!
Yes. Chi-square is used for many different fields. Especially social sciences that rely heavily on statistics.
ty!
Makes sense now! Thanks. I absolutely love your videos which is one reason why I'm passing AP Bio
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
For the last problem I gt 6.084 so I reject the null hypothesis. Thanks for the help(:
yep me too :D
technically you would Fail to Reject the Null Hypothesis according to statistics, you never want to say you Accept it
Thanks Mr. Anderson! Explained this the best way possible
Amazingly helpful video. Thanks Mr. Andersen!
Isn't it "fail to reject null hypothesis" rather then "accept"?
Yeah I think it is. Just because you fail to reject it doesn't mean it's true, you just don't reject it yet.
Someone plz link music 9:26
One of the best videos I have watched on this topic. Well explained and interesting thanks
Very well explained with good examples, thanks for the upload!