Acompany has developed a new type of light bulb, and wants to estimate its mean lifetime. a simple random sample of 12 bulbs had a sample mean lifetime of 673 hours with a sample standard deviation of 75 hours. it is reasonable to believe that the population is approximately normal. find the lower bound of the 95% confidence interval for the population mean lifetime of all bulbs manufactured by this new process.

Efficient homemakers ltd. makes canvas wallets and leather wallets as part of a money-making project. for the canvas wallets, they need two yards of canvas and two yards of leather. for the leather wallets, they need four yards of leather and three yards of canvas. their production unit has purchased 44 yards of leather and 40 yards of canvas. let x be the number of leather wallets and y be the number of canvas wallets. draw the graph showing the feasible region to represent the number of the leather and canvas wallets that can be produced.