Shorney construction company bids on projects assuming that the mean idle time per worker is 72 or fewer minutes per day. a sample of 30 construction workers will be used to test this assumption. assume that the population standard deviation is 20 minutes. a. state the hypotheses to be tested. anderson, david r.. essentials of statistics for business and economics (p. 435). south-western college pub. kindle edition.

Four airplanes carrying a total of 400 passengersarrive at the detroit airport. the airplanes carry, respectively,50, 80, 110, and 160 passengers.a) one of the 400 passengers is selected uniformly at random.let x denote the number of passengers that were on theairplane carrying the randomly selected passenger. find var(x)for x as given in the problemb) one of the 4 airplane drivers is also selected uniformly atrandom. let y denote the number of passengers on the chosen driver’s airplane. find var(y) for y as given in the problem

Can someone check if i did this correct. it’s number 4 if you’re wondering.

What is the total area of the figure?