True or false? the sum of the differences 2 (x r) is never zero for any distribution consisting of n observations.

The radius of the earth is two times the radius of the moon. what fraction of the volume of the earth is the volume of the moon?

Your friend uses c=50p to find the total cost, c, for the people, p, entering a local amusement park what is the unit rate and what does it represent in the context of the situation?

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.