A job training company advertises that the mean speed of typists from their typing

school is certain to be at least 50 letters per minute. To test this claim, the state education department

selects 16 members of the current graduating class and gives them the states standard typing test. The

results are: 51, 46, 38, 50, 43, 63, 41, 48, 52, 43, 33, 56, 68, 60, 53, and 49 letters per minute. Typing speeds

of the schools graduates are normally distributed. Test the claim and make a conclusion using a level of

significance of 0.05