Iodine-123 has a half-life of about 13 hours, emits gamma-radiation, and is readily absorbed by the thyroid.
because of these facts, it is regularly used in nuclear imaging.
a. write a formula that gives you the percent pp of iodine-123 left after t half-lives.
b. what is the decay rate per hour of iodine-123? approximate to the nearest millionth.
c. use your result to part (b). how many hours h would it take for you to have less than 1% of an initial dose of
iodine-123 in your system? round your answer to the nearest tenth of an hour.

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.