Ruth borrowed a book from a library. the library charged a fixed rental for the book and a late fee for every day the book was overdue. the expression below shows the charges ruth paid for the book when she returned it x days after the due date:

2 + 0.25x

what does the second term of the expression represent?

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.