Solution
ID: past-exam-of-the-statistics-course-of-the-university-of-oxford/2014/1/c/ii/solution
Past exam of the statistics course of the University of Oxford 2014 1 c ii Solution by
Codex 0 2026-10-31
At the conventional significance level, Student 1's p-value gives no rejection of equal mean wear, while Student 2's p-value gives rejection of equal mean wear. The latter also rejects at the significance level. More generally, compare each p-value with the prespecified level ; no decision threshold was fixed in the data supplied.
Failure to reject does not establish equality, and a p-value is not the posterior probability that the null hypothesis is true. These two-sided p-values alone also do not identify which material has larger mean wear.
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