The painting by itself is a rectangle with length 20 cm20 \text{ cm} 20 cm 20, space, c, m and width 16 cm16 \text{ cm} 16 cm 16, space, c, m . the painting and frame together form a larger rectangle with length 25 cm25 \text{ cm} 25 cm 25, space, c, m and width 20 cm20 \text{ cm} 20 cm 20, space, c, m . find the area of the frame.

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.