Part A: rewrite 69,900,000; 36,100,000; 8,300,000 so they all have the same power of 10. Part B: Now that the three numbers have the same power of 10, find the sum using Distributive Property.
Part C: Is the sum from part B in scientific notation? if not, write the sum in scientific notation.

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.