A marksman fires at the center of a target; he hits a random point (X, Y) (measured relative to the center of the target) such that X and Yare independent normal (0, a2 ) random variables. A second marksman fires, and hits at (X', yl) where X' and y' are independent with normal (0, b2 ) distributions. What is the chance that

Write two subtraction equations that are equivalent to 5 + 12 = 17.

Anyone know? will mark brainliest if correct

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.