| Exam Board | Edexcel |
|---|---|
| Module | S3 (Statistics 3) |
| Year | 2003 |
| Session | June |
| Marks | 11 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Chi-squared test of independence |
| Type | Standard 2×2 contingency table |
| Difficulty | Moderate -0.3 This is a standard 2×2 chi-squared test of independence with clearly stated hypotheses, straightforward calculation of expected frequencies, and routine application of the test procedure. While it requires multiple steps (hypotheses, expected values, test statistic, critical value comparison), all are mechanical applications of the standard algorithm with no conceptual challenges or unusual features. |
| Spec | 5.06a Chi-squared: contingency tables |
| \cline { 2 - 3 } \multicolumn{1}{c|}{} | Cold | No cold |
| Drug | 34 | 66 |
| Dummy pill | 45 | 55 |
4. A new drug to treat the common cold was used with a randomly selected group of 100 volunteers. Each was given the drug and their health was monitored to see if they caught a cold. A randomly selected control group of 100 volunteers was treated with a dummy pill. The results are shown in the table below.
\begin{center}
\begin{tabular}{ | c | c | c | }
\cline { 2 - 3 }
\multicolumn{1}{c|}{} & Cold & No cold \\
\hline
Drug & 34 & 66 \\
\hline
Dummy pill & 45 & 55 \\
\hline
\end{tabular}
\end{center}
Using a $5 \%$ significance level, test whether or not the chance of catching a cold is affected by taking the new drug. State your hypotheses clearly.\\
\hfill \mbox{\textit{Edexcel S3 2003 Q4 [11]}}