Question

5. An efficiency expert wants to determine the average amount of time it takes a particular pit crew to change a set of tires on a race car. The expert had the pit crew change a set of tires 10 times, and found that the sample mean of those times is 20 seconds and their sample standard deviation was 12.2 seconds (a) (5 points) State an appropriate interval estimator for the true average amount of time it would take the pit crew to change a set of tires. (b) (5 points) What do you have to assume to use the interval estimator you chose in Part a? (c) (5 points) Determine a 99% confidence interval for the true average amount of time it would take the pit crew to change a set of tires. The appropriate critical value is 3.25. Sketch the confidence interval. (d) (5 points) What R command would generate the critical value from Part c? e) (5 points) Give your interpretation of the confidence interval from Part c

Answer 1

(10 t 10.36 (9.6, 30, 36 e) true average tmu a a t 2.2 1 o '=2o+ 12.54 2 (3.46, 32.54) t) e) The triu ave rng 1 a.ngwJ q tim İt wond fake The