Abaker started out with 12 cups of flour. she had 91/4 cups of flour left after the first batch of batter she made. she had 61/2. cups of flour left after the second batch of batter she made. if she makes two more batches of batter, how many cups of flour will be left.

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.