Ahuman resource manager has 12 equally qualified applicants to fill a new work group that has three spots. according to company guidelines, if all 12 applicants are equally qualified, she must choose the work group of three completely at random. how many 3 person work groups are possible?

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.