A charity organization had to sell a few tickets to their fundraiser just to cover necessary production costs after selling 10 tickets, they were still a net loss of $800 (due to the product cost). They sold each ticket for $70 let y represent the net profit (in dollars) when they have sold x tickets

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.