Find the measure of the line segment de.

a) 15

b) 13

c) 21
d) 18

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.

Ablue whale traveled 3112 miles in 214hours. what was the whale's rate in yards per hour? (1 mile = 1,760 yards)

Concerned about campus safety, college officials want to estimate the percentage of students who carry a gun, knife, or other such weapon. how many randomly selected students must be surveyed in order to be 95 % confident that the sample percentage has a margin of error of two percentage points?