U4 - Scatter diagrams and correlation

Question 1

When is it more appropriate to use Pearson’s product moment correlation coefficient over spearman’s rank correlation coefficient?

Answer 1

When there’s a linear relationship. Spearman’s rank is more suitable for non-linear correlation.

Question 2

Correlation meanings in spearman’s rank

Answer 2

> 0.8 or < -0.8 = strong correlation
0.4 to 0.8 or -0.4 to -0.8 = weak correlation
<0.4 or > -0.4 = no correlation

Question 3

What does PMCC measure?

Answer 3

The strength of linear correlation between two sets of data

Question 4

What is non linear correlation?

Answer 4

Any correlation in which the rates of change of the variables is not constant