Calculate the correlation co-efficient between the heights of fathers in inches (X) and their son (Y)
|
X |
65 |
66 |
57 |
67 |
68 |
69 |
70 |
72 |
|
Y |
67 |
56 |
65 |
68 |
72 |
72 |
69 |
71 |
|
X |
dX (d from AM = 67) |
dX2 |
Y |
dY (d from AM = 68) |
dY2 |
dXdY |
|
65 |
–2 |
4 |
67 |
–1 |
1 |
2 |
|
66 |
–1 |
1 |
56 |
–12 |
144 |
12 |
|
57 |
–10 |
100 |
65 |
–3 |
9 |
30 |
|
67 |
0 |
0 |
68 |
0 |
0 |
0 |
|
68 |
+1 |
1 |
72 |
4 |
16 |
4 |
|
69 |
+2 |
4 |
72 |
4 |
16 |
8 |
|
70 |
+3 |
9 |
69 |
1 |
1 |
3 |
|
72 |
5 |
25 |
71 |
3 |
9 |
15 |
|
ΣX = 534 |
ΣdX = –2 |
Σ dX2 = 144 |
ΣY = 540 |
ΣdY = –4 |
ΣrfY2 = 196 |
ΣdXdY = 74 |
Calculate the correlation co-efficient between X and Y and comment on their relationship.
|
X |
–3 |
–2 |
–1 |
1 |
2 |
3 |
|
Y |
9 |
4 |
1 |
1 |
4 |
9 |
Hence, r = 0
Two values X and Y are un-corrected.
There is no linear correlation between them.
Why does rank correlation coefficient differ from Personian correlation co-efficient?
Because rank correlation co-efficient provides a measure of linear association between ranks assigned to these limits and not their values.
Measure the height of your classmates. Ask them the height of their benchmate:Calculate the correlation coefficient of these two variables. Interpret the result
Try yourself.
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