A sample of 20 items from manufacturer A were measured and a sample mean of 2376.3 and a sample standard deviation of 24.1 were obtained. Also, a sample of 24 items from manufacturer B were measured and a sample mean of 2402.0 and a sample standard deviation of 26.4 were obtained.
(a) Use a one-sided hypothesis test to assess whether there is sufficient evidence to conclude that the items from manufacturer B provide larger measurements on average than these items from manufacturer A.
(b) Construct a 95% one-sided confidence interval that provides an upper bound on how much larger on average the measurements of the items from manufacturer B are compared with the items from manufacturer A.