Moderate -0.3 This is a straightforward binomial hypothesis test with clearly stated hypotheses (one-tailed test of p=0.9), requiring calculation of P(X≤11) under H₀ and comparison to 5% significance level. All parameters are given, and the method is standard A-level procedure with no conceptual complications, making it slightly easier than average.
Pierre is a chef. He claims that 90% of his customers are satisfied with his cooking. Yvette suspects that Pierre is over-confident about the level of satisfaction amongst his customers. She talks to a random sample of 15 of Pierre's customers, and finds that 11 customers say that they are satisfied. She then performs a hypothesis test.
Carry out the test at the 5% significance level. [7]
Pierre is a chef. He claims that 90% of his customers are satisfied with his cooking. Yvette suspects that Pierre is over-confident about the level of satisfaction amongst his customers. She talks to a random sample of 15 of Pierre's customers, and finds that 11 customers say that they are satisfied. She then performs a hypothesis test.
Carry out the test at the 5% significance level. [7]
\hfill \mbox{\textit{OCR H240/02 2020 Q10 [7]}}