The probability of an outcome that lies within 68% of the mean is a good indicator that it lies in which standard deviation? a. there is a probability that the outcome is within 3 standard deviations of the mean. b. standard deviations are not reliable, so the probability cannot be determined. c. there is a probability that the outcome is within 2 standard deviations of the mean. d. there is a probability that the outcome is within 1 standard deviation of the mean.

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.

What is the volume of this container?

Tell whether the two rates form a proportion