Acompany employs two shifts of workers. each shift produces a type of gasket where the thickness is the critical dimension. the average thickness and the standard deviation of thickness for shift 1, based on a random sample of 38 gaskets, are 10.86 mm and 0.14 mm. the similar figures for shift 2, based on a random sample of 35 gaskets, are 10.88 mm and 0.17 mm. let μ1 — μ2 be the mean difference in thickness between shifts 1 and 2. part a) find a 95% confidence interval for µ1-µ2.
part b) based on your answer to part a, are you convinced that the gaskets from
shift 2 are, on average, wider than those from shift 1? why or why not?
part c) how would your answers to parts a and b change if the sample sizes
were instead 300 and 250?