Correlation: sign and coefficient

Example 1 · level 1

What type of correlation would you expect between: Hours of self-study and marks scored?

1. Negative
2. Positive
3. No correlation

Example 2 · level 2

For two series, Cov(x, y) = 9.6, σx = 4 and σy = 6. Find Karl Pearson’s coefficient of correlation.

Example 3 · level 3

The regression coefficients are byx = 0.5 and bxy = 0.5. Find the coefficient of correlation r.