Question

11. (10 pts) Researchers are calling for closer scrutiny of milk after reports have shown that vitamin D levels often failed to reach or exceed federal standards. In an independent study of 20 containers of milk, the mean and standard deviation of the number of units of vitamin D were x = 365 and s = 46. Determine at the 0.05 level of significance whether the mean number of units of vitamin D is less than 400, the amount required by the Food and Drug Administration.

Answer 1