Topic 11

Question 1

Correlation

Answer 1

The strength of the linear association between two variables

Question 2

Pearson Correlation Coefficient

Answer 2

r = Σ n, i=1 (xi-x~)(yi-y~) / √Σ n, i=1 (xi-x~)^2 √Σ n, i=1 (yi-y~)^2 where xi and yi are individual values of two variables and x~ y~ are the mean values

Question 3

Correlation Coefficient Randomisation Test

Answer 3

Randomise the order of the observations for one variable and keep the order of the other fixed. Calculate r for each randomisation. After repeating, find the percentile of the observed r-score with respect to this distribution