Question 1 1/ 1 point A dishwasher has a mean life of 12 years with an estimated standard deviation of 1.25 years ("Appliance life expectancy," 2013). Assume the life of a dishwasher is normally distributed. Find the number of years that the bottom 25% of dishwasher would last. Round answer to 2 decimal places. Answer: 11.16 v p—— ¥ T 1 Sy, w Hide question 1 feedback In Excel, =NORM.INV(0.25,12,1.25) Question 2 1/ 1 point Arm span is the physical measurement of the length of an individual's arms from fingertip to fingertip. A man's arm span is approximately normally distributed with mean of 70 inches with a standard deviation of 4.5 inches. Find length in inches of the 99th percentile for a man's arm span. Round answer to 2 decimal places. Answer: 80.47 v ——— e —— w Hide question 2 feedback In Excel, =NORM.INV(0.99,70,4.5) Question 3 0/ 1 point Find the area under the standard normal distribution to the left of z = -1.05. Round answer to 4 decimal places. Answer: 0.1474 % (0.1469, .1469) et S f 8 . w Hide question 3 feedback In Excel, =NORM.S.DIST(-1.05,TRUE)
