A researcher compares the spatial memory scores of professional chess players (n=24n = 24n=24) and non-players (n=18n = 18n=18) using a standardized interval-level memory test. The scores in the general population are normally distributed. However, when analyzing the sample data, the researcher finds that the variance for the chess players is 11.4 while the variance for the non-players is 78.2.
Why is the researcher unable to use a parametric test (such as the unrelated ttt-test) to analyze this data?
The sample sizes of the two groups are unequal (n=24n = 24n=24 and n=18n = 18n=18).
The variances of the two groups are highly dissimilar, violating the assumption of homogeneity of variance.
The data is measured at the interval level, which is inappropriate for parametric analyses.
The underlying population from which the samples were drawn is normally distributed.
513 exam-style questions on OCR A Level Psychology Data recording, analysis and presentation. Each one has a worked solution and a mark scheme showing where the marks go.