Standard +0.8 This is a Mann-Whitney U test (Wilcoxon rank-sum test) requiring students to: identify the appropriate non-parametric test, calculate the test statistic from rank sums, find critical values or use normal approximation, and conduct a two-tailed hypothesis test. While the calculation is relatively straightforward once the method is identified, choosing the correct non-parametric test and properly executing the procedure with continuity correction places this above average difficulty for A-level, though it remains a standard application of the syllabus content.
A university course was taught by two different professors. Students could choose whether to attend the lectures given by Professor \(Q\) or the lectures given by Professor \(R\). At the end of the course all the students took the same examination.
The examination marks of a random sample of 30 students taught by Professor \(Q\) and a random sample of 24 students taught by Professor \(R\) were ranked. The sum of the ranks of the students taught by Professor \(Q\) was 726.
Test at the 5% significance level whether there is a difference in the ranks of the students taught by the two professors. [10]
A university course was taught by two different professors. Students could choose whether to attend the lectures given by Professor $Q$ or the lectures given by Professor $R$. At the end of the course all the students took the same examination.
The examination marks of a random sample of 30 students taught by Professor $Q$ and a random sample of 24 students taught by Professor $R$ were ranked. The sum of the ranks of the students taught by Professor $Q$ was 726.
Test at the 5% significance level whether there is a difference in the ranks of the students taught by the two professors. [10]
\hfill \mbox{\textit{OCR Further Statistics 2021 Q5 [10]}}