Statistics 1024b Section 570 Homework assignment 4 | Complete Solution

Statistics 1024b
Section 570 Homework assignment 4

The responses to these question must be handed in at the beginning of the class on Thursday, March 26. At most, you will be expected to hand in your work on ONE SIDE OF A SINGLE SHEET of paper. The work will be graded out of 8 marks, with a minimum of 2 marks for handing in something.

1. (a) A physiology researcher took a random sample of 100 students and found that their average blood pressure was 122 mmHg. Assume that the population standard deviation is 10 mmHg, and nd a 95% con dence interval for , the population mean. (2 marks) (b) Why is 95% a reasonable number? (1 mark)

2. Suppose that previous records show that the average height of King's students is 172 cm. You suspect that the current students are taller than that average. You take a random sample of 25 students, and get a sample mean of 176 cm. You know that the population standard de- viation is 10 cm. Using an level of 0.05, conduct a test of hypothesis, and come to a conclusion about the average height of current students.
(3 marks)
NB. do NOT use the word signi cant in your answer.

3. Use the con dence interval in 1)(a) to test the hypothesis that the average blood pressure is not 120 mmHg. (2 marks)