Mechanics agree that the chain on a bicycle should be replaced after covering an average of 3000 miles. StakRide is a new bicycle manufacturing company and it wants to check if the chains it produces for bicycles have a longer life span than the existing average. The lead mechanic randomly selects 25 of the new bicycles and test runs them. The resulting sample mean and standard deviation are 3050 miles and 85 miles, respectively. a) What hypothesis should be tested to determine whether the life span of StakRide bicycle chains is longer than the known average? (3 marks) b) Assuming that the life span of the bicycle chains is approximately normal, what test statistic would you use to test the hypotheses in part(a)? What is the value of the test statistic for this data? (3 marks) c) What conclusion would you reach for a significance level of 0.05. (4 marks)

Question 4 Mechanics agree that the chain on a bicycle should be replaced after covering an average of 3000 miles. StakRide is a new bicycle manufacturing company and it wants to check if the chains it produces for bicycles have a longer life span than the existing average. The lead mechanic randomly selects 25 of the new bicycles and test runs themr The resulting sample mean and standard deviation are 3050 miles and 85 miles. respectively. a) What hypothesis should be tested to determine whether the life span of StakRide bicycle chains is longer than the known average? {3 marks) b) Assuming that the life span of the bicycle chains is approximately normal, what test statistic would you use to test the hypotheses in part(a)? What is the value of the test statistic for this data? (3 marks} c) What conclusion would you reach for a signicance level of 0.05. {4 marks}