Adam invested $12,000 in a six-year cd that paid 7.1% interest, but later needed to withdraw $2,500 early. if the cd’s penalty for early withdrawal was eighteen months’ worth of interest on the amount withdrawn, how much of a penalty did adam pay?

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.