Lin found the area of a rectangle with a of length 5 in and a width of 3 inches, to be 15 square inches. Lin creates another rectangle that is a scaled copy with a scale factor of 2. What is the area of the new rectangle? How did you find it?

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.