The results of a series of surveys revealed a population with a mean of 15 and a standard deviation of 1.88. If each survey has a sample size of 70, which value falls within the interval where 95% of the sample means occur? 14.34 15.49 14.96 15.66

Monitors manufactured by tsi electronics have life spans that have a normal distribution with a standard deviation of 1800 hours and a mean life span of 20,000 hours. if a monitor is selected at random, find the probability that the life span of the monitor will be more than 17,659 hours. round your answer to four decimal places.