AN EASY, STEP BY STEP METHOD OF CALCULATING CORRELATION COEFFICIENT IS DISCUSSED HERE. VARIOUS TYPES OF PROBLEMS WITH FORMULAE ARE ILLUSTRATED. THIS COULD BENEFIT GRADE 11 MATH STUDENTS AND COLLEGE STUDENTS LEARNING STATISTICS.

1. CORRELATION
GRADE 11 MATH
COLLEGE MATH
r 𝜚

2. PREVIEW:
THIS VIDEO ILLUSTRATES THE METHOD OF CALCULATING
CORRELATION.
THE METHOD OF CALCULATING COVARIANCE IS ALSO DISCUSSED.
DIFFERENT TYPES OF PROBLEMS USING DIFFERENT FORMULAE ARE
DISCUSSED.
SO STAY RIGHT THROUGH THE ENTIRE VIDEO!

3. Correlation is used to measure the degree of variations in 2variables.
We first define Covariance between 2 variables x and y

4. Karl Pearson’ s coefficient of correlation

7. r has a moderate degree of negative correlation.
If
r has a low degree of negative correlation.

9. Let u =x-A, v = y-B

10. 1) Find r if cov(x,y)=-16.5 var(x)=2.25,
Var(y) =144

11. 2) If n = 10,
Find the correlation coefficient
𝑛 𝑥𝑦 − 𝑥 𝑦
𝑛 𝑥2 − ( 𝑥)2 𝑛 𝑦2 − ( 𝑦)2
226

13. Question 3
The coefficient of correlation between 2 variables x and y is 0.64. Their
covariance is 16. Variance of x is 9. Find the standard deviation of y

14. Question 4
Find the covariance and coefficient of correlation between x and y
when n=10

15. r =

16. Question 5
Calculate coefficient of correlation for the following

18. Question 6
Calculate Karl Pearson’s coefficient of correlation
Sales in lakhs Expenditure in lakhs
18 23
20 27
27 28
20 28
21 29
29 30

19. Sales Expenditure u v uv
18 23 - 5 - 5 25 25 25
20 27 - 3 -1 3 9 1
27 28 4 0 0 16 0
20 28 - 3 0 0 9 0
21 29 -2 1 - 2 4 1
29 30 6 2 12 36 4

20. r =

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