A researcher conducts an experiment to compare the reaction times (in milliseconds) of two independent groups of participants under different noise conditions. They intend to use an unrelated ttt-test to analyse the data. Which of the following findings from the preliminary data analysis would violate the assumptions of this parametric test, thereby requiring the researcher to use a non-parametric alternative?
The standard deviations of the reaction times in the two groups are highly similar (s1=15.2 mss_1 = 15.2\text{ ms}s1=15.2 ms and s2=16.0 mss_2 = 16.0\text{ ms}s2=16.0 ms).
The dependent variable (reaction time) is measured in milliseconds, which represents a ratio level of measurement.
The distribution of reaction times in one of the groups is highly skewed (p<0.01p < 0.01p<0.01 on a test of normality).
The total sample size of the study is large (N=80N = 80N=80), with equal numbers of participants in each group.
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.