Mrs. Miller's geometry test scores are normally distributed with a mean score of 70 (μ) and a standard deviation of 3 (σ). Using the Empirical Rule, about 95% of the scores lie between which two values?

Atemperature of 1.64◦f corresponds to answer in units of ◦c.

Which number completes the inequality? 2/3 < _ < 7/9

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.