Different days for certain numbers of hours. Day Number of Hours to Babysit
Monday
9.5
Tuesday
7
Wednesday
7.5
Thursday
9
Friday
8.5
Saturday
On which day(s) can Tracy babysit for enough hours to afford to purchase her bike?
Select ALL that apply.
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday

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.