Correlation

The unit of correlation coefficient between height in feet and weight in kgs is

The range of simple correlation coefficient is

If rxy is positive the relation between X and Y is of the type

If rxy = 0 the variable X and Y are

Of the following three measures which can measure any type of relationship

If precisely measured data are available the simple correlation coefficient is

Why is r preferred to covariance as a measure of association?

Can r lie outside the -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 independence?

Can simple correlation coefficient measure any type of relationship?

Collect the price of five vegetables from your local market every day for a week. Calculate their correlation coefficients. Interpret the result.

Measure the height of your classmates. Ask them the height of their benchmate. Calculate the correlation coefficient of these two variables. 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 Pearsonian correlation coefficient?

Calculate the correlation coefficient between X and Y and comment on their relationship: X: -3, -2, -1, 1, 2, 3 Y: 9, 4, 1, 1, 4, 9 (Ans. r = 0)

Calculate the correlation coefficient between X and Y and comment on their relationship X: 1, 3, 4, 5, 7, 8 Y: 2, 6, 8, 10, 14, 16 (Ans. r = 1)