Ben and Cam are scuba diving. Ben is 15.8 meters below the surface of the water. Cam is 14.2 meters above Ben. What is Cam’s position relative to the surface of the water?
A) 11.6 meters above the surface of the water
B) 11.6 meters below the surface of the water
C) 20 meters above the surface of the water
D) 20 meters below the surface of the water

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.