Paper 2, Section I, H
Part IB, 2016
The efficacy of a new medicine was tested as follows. Fifty patients were given the medicine, and another fifty patients were given a placebo. A week later, the number of patients who got better, stayed the same, or got worse was recorded, as summarised in this table:
\begin{tabular}{|l|c|c|} \hline & medicine & placebo \ better & 28 & 22 \ same & 4 & 16 \ worse & 18 & 12 \ \hline \end{tabular}
Conduct a Pearson chi-squared test of size of the hypothesis that the medicine and the placebo have the same effect.
[Hint: You may find the following values relevant: