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Correlation
Write down the steps involved in calculating correlation co-efficient by step deviation method.
Steps involved in calculating correlation Co- efficient by step - deviation:
1. Take the assumed mean of X series.
2. Take the assumed mean of Y series.
3. Calculate deviations of X and Y from assumed mean and name them dX and dY respectively.
4. Divide dX and dY by convenient common factor to reduce the calculations. This is also called change of origin and change of scale of the values of X and Y. The value of co- efficient of correlation is unaffected by the change in origin and change of scale if X and Y. After changing the deviations we apply the same formula of assumed mean method.
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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?
Measure the height of your classmates. Ask them the height of their benchmate:Calculate the correlation coefficient of these two variables. Interpret the result
Calculate Karl Pearson’s correlation co-efficient bv the assumed mean method.
|
X |
14 |
15 |
18 |
20 |
25 |
30 |
|
Y |
40 |
45 |
65 |
28 |
30 |
40 |
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 |
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