A-Level Biology - Pearson's correlation coefficient

[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!

Visit my FB page : D Biology Classroom.

#biology #alevel #alevelbiology #caie #alevelrevision

[DBiologyClassroom]

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!

[anandr]

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

[aryaa]

hi my bio teacher told me to watch this for my assignment but i found more of your formulas and theyre really interesting! <3 subscribed and liked cus no one does it better than david senpai

[mariavincent]

Great presentation David. You're a great teacher. Your explanation was crystal clear and precise. Thank you very much.

[izzatulain]

shout out to you because i can totally understand !!

[ironman]

Super useful for my p5 thanks so much!

[angxliaa]

thankyouuu so muchh for the great explanation!! i understood your explanation very well. ☺️👍🏻

[aselweerasekara]

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<0.632.
Please let me know, you've made this extremely hard theory much more understandable for me.

Thanks .

[rimshaasif]

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?

[winxclubflora]

Sir is the null hypothesis always the same that there is no correlation?

[laavanya]

Pls tell me why we take x as the caffeine concentration

[peaceandloveonthisplanetea]

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!

[jeonjk]

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?

[whitneypadayachy]

Where did you get the value of Sy? From which data?

[ironman]

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?

[ruraaak]

Why is the degree of freedom n-2? Instead of n-1?