A-Level Biology - Pearson's correlation coefficient
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- Опубліковано 1 лип 2024
- [D Biology Classroom] CAIE A-level biology 9700
What is Pearson's correlation coefficient? How to use it for problem-solving?
*** At 2:35, I made a mistake by writing 294100 as 29410. However, the calculation is correct. My apology for that !!
*** In the 2022-2024 syllabus, the formula is changed to (n-1)SxSy, no longer nSxSy as shown in this video. Do take note of that!
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In the 2022-2024 syllabus, the formula is changed to (n-1)SxSy, no longer nSxSy as shown in this video. Do take note of that!
Sir will the formulas be stated or do we have to memorize them?
@@aleena158 it will be given. You don't have to memorise any formula of the statistical test.
Wow, this is great. Even if u dont know anything u can learn this easily within minutes. Thank u David de lecturer and keep it up. Found it helpful
Good to hear that ! :)
hi my bio teacher told me to watch this for my assignment but i found more of your formulas and theyre really interesting!
long live david da lecturer
Haha thank you for that. Glad that my videos help !
Should I use water or set wavelength to calibrate colorimeter to zero
Great presentation David. You're a great teacher. Your explanation was crystal clear and precise. Thank you very much.
Thank you for the kind words !
Yess I got it thank you so much:)
Many blessings upon you. Thank you.
Same to you!
shout out to you because i can totally understand !!
Glad that I can help :)
thankyouuu so muchh for the great explanation!! i understood your explanation very well. ☺️👍🏻
you are so welcome :)))
Really helpful! Love the vids
You are welcome!!
thank you!!!
You're welcome!
Thank youu soo mcuh!!!!!
You are welcome!!!
Super useful for my p5 thanks so much!
You are welcome 😀😀
THANK YOUU !!!
You are welcome !
Thank youuu!
Ps: sir i have a question. I watched your T-test video. In that video you calculated the degree of freedom by adding both no of samples of both the datas given and than subtracting with 2. Like (nA +nB)-2.
In this video you subtracted 2 from only 10.
Is degree of freedom calculated differently in every test?
Yes you are right. Different statistical test has different definitions for the degrees of freedom.
At 2:35 the person's correlation formula the sum value of XY should be 291400 right? it's written as 29140.
Also at 4:30,
the calculated r is -0.864 right? So when you are comparing the critical value with the calculated value, do you ignore the (+) and (-) values ? Because only if you do it becomes
0.864>0.632
Otherwise, if the minus sign is taken to account it would be
-0.864
Hi, thanks for pointing it out, I missed one 0 on 2:35.
And yes, refer to 3:45. The negative sign has to be ignored.
@@DBiologyClassroom thank you very much
Really helpful!!!!
Thank u 😁
Very helpful thanks
You are welcome!
Sir for spearman's rank and pearson's linear correlation, what would be null hypothesis?
is this correct: There is no significant correlation between the two variables
And for t-test and chi sq: There is no significant difference between the means (t-test)/ observed and expected values (chi test)
For Simpson's index of diversity there cannot be a null hypothesis right?
Yup, all are correct. Simpson is a calculation, not a test, so there is no null hypothesis.
You're amazing 💓💓💓💓💓💓💓
Thank you :)
Hi Mr David. In the specification, to calculate the r value, for the the denominator side, it is *(n-1)SxSy* but you have written *nSxSy*
Has the syllabus changed and past papers will have ur formula or you jus made a mistake? Great videos btw they’re really helping me!
Hi, yes, they changed the formula. It is n-1 now. They will give you the formula during the examination so follow the one they give you. cheers !
Sir, at 1:46 will we also be given with the representatives of the letters (such as n=sample size) of formula in the main exam in 2023?
Hi, they will give you the formula but not necessarily with the key. So it's better for you to remember what those symbols represent.
Sir is the null hypothesis always the same that there is no correlation?
yup that's true
Pls tell me why we take x as the caffeine concentration
that is the independent variable
Where did you get the value of Sy? From which data?
Y is the mean reaction time. Sy is the standard deviation of those data.
Why is the degree of freedom n-2? Instead of n-1?
Hi, it is because you have to minus 1 from each set of data. you have 2 sets - x and y, so minus 2.
@@DBiologyClassroom thank you!!!!
@@ruraaak2868 You are welcome !
sir why n-2 instead of n -1
Hi, it is because there are two variables.
will the formula be given
All statistical rest formulas will be given