Normal and Sampling Distributions
Q1.The life of cell batteries is normally distributed with a mean of 88.2 hours and a standard deviation of 15.5 hours. 93% of the batteries will last more than how many hours? (2 decimal places )
Q2.The length of time for long-distance phone calls has been found to be normally distributed, with a mean of 23.2 minutes and a standard deviation of 6.7 minutes. In a randomly selected sample of 59 calls, what is the sample average call time below which 10% of sample average call times will be shorter?