9. Correlation tests

Question 1

What is a correlation coefficient? (Methods1 correlations)

Answer 1

Measure of the strength of the relationship between two variables

Question 2

What two ways can a correlation coefficient be measured? (Methods1 correlations)

Answer 2

• Pearson’s r

- Spearman’ rho

Question 3

When is Pearson’s r used? (Methods1 correlations)

Answer 3

• 2 variables
• Continuous data
• Interval or ratio

Question 4

Is Pearson’s r a parametric or non-parametric test? (Methods1 correlations)

Answer 4

Parametric because the data must have specific characteristics before it can be used

Question 5

What is r2 and what does it show us? (Methods1 correlations)

Answer 5

• The coefficient of determination

- What proportion of the variation in the Y scores is associate with the change in X scores

Question 6

What is R2 and what does it tell us? (Methods1 correlations)

Answer 6

• The effect size

- The practical strength of the relationship

Question 7

When is Spearman’s rho used? (Methods1 correlations)

Answer 7

• Continuous data

- Ordinal data

Question 8

Is Spearman’s rho a parametric or non-parametric test? (Methods1 correlations)

Answer 8

Non-parametric

Question 9

When ranking data, what happens when there is a tie? (Methods1 correlations)

Answer 9

Give the tie the average ranks they would have obtained had they been different . The next score gets the rank it would have, if the previous scores had not been tied