Question
Calculate the Karl Pearson’s correlation co-efficient by the assumed mean method.
|
X |
85 |
82 |
82 |
79 |
80 |
45 |
65 |
49 |
85 |
85 |
|
Y |
62 |
80 |
80 |
63 |
64 |
61 |
68 |
70 |
80 |
80 |
Solution
|
X |
Y |
dX (X-85) |
dY(Y–82) |
dXdY |
dX2 |
dY2 |
|
85 |
62 |
0 |
– 18 |
0 |
0 |
324 |
|
82 |
80 |
–3 |
0 |
0 |
9 |
0 |
|
82 |
80 |
–3 |
0 |
0 |
9 |
0 |
|
79 |
63 |
–6 |
– 17 |
102 |
36 |
289 |
|
80 |
64 |
–5 |
– 16 |
80 |
25 |
256 |
|
45 |
61 |
– 40 |
– 19 |
360 |
1600 |
361 |
|
65 |
68 |
– 20 |
– 12 |
240 |
400 |
144 |
|
49 |
70 |
– 36 |
– 10 |
360 |
1296 |
100 |
|
85 |
80 |
0 |
0 |
0 |
0 |
0 |
|
85 |
80 |
0 |
0 |
0 |
0 |
0 |
|
ΣdX= –113 |
Σ dY= –92 |
Σ dXdY = 1542 |
Σ dX2= 3375 |
ΣdY2= 1474 |
Assumed mean of X = 85 Assumed mean of Y = 80
