9231 P43 - Jun 2025 - Q5 - 8 marks
6658
A doctor is investigating the concentration of blood glucose in patients at risk of developing type 2 diabetes, where blood glucose is measured in appropriate units. The doctor claims that a particular intervention reduces the concentration by more than \(k\) units on average. A group of 8 at risk patients is selected at random and each patient follows the intervention for six months. The blood glucose concentrations before and after the intervention are given in the following table.
Patient | \(A\) | \(B\) | \(C\) | \(D\) | \(E\) | \(F\) | \(G\) | \(H\) |
|---|---|---|---|---|---|---|---|---|
Before | 183 | 165 | 172 | 165 | 143 | 176 | 161 | 153 |
After | 164 | 148 | 164 | 149 | 134 | 153 | 155 | 148 |
(a) Use a \(t\)-test at the \(5 \%\) significance level to find the range of values of \(k\) for which the result of the test is to reject the null hypothesis.
(b) State an assumption necessary for the test in part (a) to be valid.
Solutions and mark schemes for 9231 are temporarily available to admins only.