A clinical psychologist measures the anxiety levels of patients in two groups using a standardized scale that yields interval-level scores. The variance of anxiety scores is 15.4 for Group A and 16.2 for Group B. The scores in both groups are normally distributed. Which of the following statements correctly identifies the appropriate type of statistical analysis and the reason for its selection?
A non-parametric test, because the variances are homogeneous but the data level is only interval.
A parametric test, because the data are interval level, normally distributed, and the variances are homogeneous.
A non-parametric test, because although the data are interval and normally distributed, the unequal variances (15.415.415.4 and 16.216.216.2) indicate severe heterogeneity.
A parametric test, because any normally distributed data can be analyzed parametrically regardless of the level of measurement or variance.
644 exam-style questions on OCR A Level Psychology Research methods and techniques. Each one has a worked solution and a mark scheme showing where the marks go.