question 2

FP-Q.2 ( 5 marks) The recommended daily allowance of iron for females aged 19-50 is 18 mg/day. A careful measurement of the daily iron intake of 15 women yielded a mean daily intake of 16.2 mg with sample standard deviation 4.7 mg. We assume that daily iron intake in women is normally distributed. (a) (1.0 mark) Construct a 90 % confidence interval for the actual mean daily intake for all women. (b) (0.5 mark) Based on your result in (a), perform the test that the actual mean daily intake for all women is different from 18 mg/day, at the 10% level of significance. (c) (1.5 mark) The sample mean is less than 18, suggesting that the actual population mean is less than 18 mg/day. Using the observed significance approach, perform this test, also at the 10% level of significance. (d) (1.0 mark) Perform the test in (c) using the critical value approach, also at the 10% level of significance. (e) (1.0 mark) Compute the power of the test in (c) if the actual population mean is 15 mg/day. 1