Suppose we take 53 samples from a population whose mean is 45 with a standard deviation of 4. Describe the shape of the means of the sampling distribution. Do we
need to make any assumptions about that data? Why or why not?

Find the area of a trapezoid with a height of 23, base 1 of 10 and base 2 of 18

An automobile assembly line operation has a scheduled mean completion time, μ, of 12 minutes. the standard deviation of completion times is 1.6 minutes. it is claimed that, under new management, the mean completion time has decreased. to test this claim, a random sample of 33 completion times under new management was taken. the sample had a mean of 11.2 minutes. assume that the population is normally distributed. can we support, at the 0.05 level of significance, the claim that the mean completion time has decreased under new management? assume that the standard deviation of completion times has not changed.

Find two numbers if their sum is 91 and the ratio is 6: 7?