+91-8076753736 [email protected]

-->

Correlation

Question

Wired Faculty App

Calculate Karl Pearson’s Correlation co-efficient from the following data:

X

78

89

97

69

59

79

68

61

Y

125

137

156

112

107

136

123

108

Solution

Calculation of Karl Pearson’s correlation co-efficient

X	dX	dX²	Y	dY	dY²	dXdY
78	9	81	125	13	169	117
89	20	400	137	25	625	500
97	28	784	156	44	1936	1232
69	0	0	112	0	0	0
59	–10	100	107	–5	25	50
79	10	100	136	24	576	240
68	–1	1	123	11	121	–11
61	–8	64	108	–4	16	32
N=8	ΣdX = 48	ΣdX² =1530	N = 8	ΣdY = 108	ΣdY² = 3468	ΣdXdY = 2160

A.M. of X series 69 assumed mean of Y series = 112

Some More Questions From Correlation Chapter

Why is r preferrred to co-variance as a measure of association?

Can r lie outside -1 and 1 range depending on the type of data?

Does correlation imply causation?

When is rank correlation more precise than simple correlation coefficient?

Does zero correlation mean independenc?

Can simple correlation coefficient measure any type of relationship?

Collect the price of five vegetables from your local market everyday for a week. Calculate their correlation coefficient. Interpret the result.

List some variables where accurate measurement is difficult.

Interpret the values of r as 1, –1 and 0.

Why does rank correlation coefficient differ from Personian correlation co-efficient?

Mock Test Series

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation