question 5 (A , B and C)

Question 5 (a) How large a sample of federal employees in Nevada should be taken if we want to estimate with 98% confidence the mean salary to within $2,000. The population standard deviation is assumed to be $10,500. (3 marks) (b ) Suppose the average weight for adult males (age 18 or older) in Alachua County is 190 Ibs (pounds) with a standard deviation of 20. Now suppose we take a random sample of 143 adult males (age 18 or older) in Alachua County. What is the probability that the average weight of our 143 subjects is bigger than 193 Ibs (pounds)? (3 marks) (c) A manufacturer claims that his camera can take not more than 7 photographs per second. A test over 49 cameras selected at random shows that the mean number of photographs in a second is 6.9 with a standard deviation of 0.58. Set up the hypothesis and does this test provide evidence to reject the manufacturer's claim, at o = 0.05? (4 marks)