Stats tests

Question 1

What is the correlation technique testing for? Provide examples of tests…

Answer 1

Is there an association between variables?

1. Pearson correlation (strength of association between two continuous variables).
2. Spearman correlation (strength of association between two ordinal variables).
3. Chi-squared (strength of association between two categorical variables).

Question 2

What tests would you apply to compare the means between two or more sets of data?

Answer 2

1. Paired t-test (different variables from the same population eg. pre- and post-test).
2. Independent t-test (same variable from different population).
3. ANOVA (same variable from different population after accounting for another variable).

Question 3

What is regression analysis?

Answer 3

Tests for a relationship

1. Simple regression (one predictor variable).
2. Multiple regression (two or more predictor variables).

Question 4

What is a non-parametric test and when is it used?

Answer 4

When data does not have a normal distribution

1. Wilcoxon Rank-Sum (difference between two independent variables taking into account the magnitude and direction of difference).
2. Chi squared