Correlation

Question 1

correlation

Answer 1

assesses the degree to which scores on two variables are related

Question 2

correlation coefficient (r)

Answer 2

index of the extent to which two variables are linearly correlated (strength)

Question 3

Pearson’s Product-moment correlation coefficient (r)

Answer 3

used when there is a (1) linear monotonic relationship with no outliers and must be measured on (2) interval scales

report
was the correlation significant?
was the correlation positive/negative, weak/moderate/strong?
what were the variables?
r(N-2) = [r-value], p = [p-value]
what does this suggest?

Question 4

spearman’s rank correlation coefficient (rs)

Answer 4

monotonic but non linear (curved graph) or if there are outliers
non-monotonic (u-shaped) - different analysis

report
explain why Rs if being used (outliers, non-linear)
strength and direction of relationship
variables investigating
what test was used (spearman’s rank correlation coefficient)
rs(N-2) = [Rs-value], p = [p-value]
what does this suggest?

Question 5

partial correlation

Answer 5

used when you want to control for a ‘third variable’
measured the strength of relationship whilst controlling for a third variable

report
what kind of correlation analysis used?
what is it measuring (strength between two variables - list variables)
what was it controlling for?
significance, direction and strength?
r(df) = [r-value], p = [p-value]
what does this suggest