Mom and Grandma are each baking chocolate chip cookies. Each gives you two cookies. One of Mom’s cookies has 14 chips in it and the other has 11. Grandma’s cookies have 6 and 8 chips. e. Estimate how many more chips there are on the average in one of Mom’s cookies than in one of Grandma’s. Find the uncertainty in this estimate.

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.