According to the Department of Education, college students spend an average of 150 minutes per day on their phones with a standard deviation of 75 minutes. Suppose a random sample of 36 college students is taken and the mean time is spent on phones is recorded.

(a) What is the probability that sample mean is less than 140 minutes per day?

Find the solution of each of the following.

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.

Hurry if the population of of an ant hill doubles every 10 days and there are currently 100 ants living in the ant hill what will the ant population be in 20 days