Drag the tiles to the correct boxes to complete the pairs. Add each pair of monomials and match it to the correct sum.

-15u3 + 5u3
10u3 + (-5u3)
10u3 + 5u3
5u3 + (-10u3)

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.