9231 P41 - Nov 2023 - Q3 - 8 marks
6687
Scientists are studying the effects of exercise on LDL blood cholesterol levels. Over a three-month period, a large group of people exercised for 20 minutes each day. For a randomly chosen sample of 10 of these people, the LDL blood cholesterol levels were measured at the beginning and the end of the three-month period. The results, measured in suitable units, are as follows.
| Person | A | B | C | D | E | F | G | H | I | J |
|---|---|---|---|---|---|---|---|---|---|---|
| Beginning | 72 | 84 | 120 | 90 | 102 | 135 | 64 | 75 | 80 | 88 |
| End | 64 | 76 | 105 | 92 | 105 | 115 | 67 | 75 | 75 | 84 |
(a) Test, at the \(2.5\%\) significance level, whether there is evidence that the population mean LDL blood cholesterol level has reduced by more than 2 units after the three-month period.
(b) State any assumption that you have made in part (a).
Solutions and mark schemes for 9231 are temporarily available to admins only.