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Cell Phone Lifetimes A recent study of the lifetimes of cell phones found the average is 24.3 months. The standard deviation is
2.6 months. If a company provides its 35 employees with a cell phone, find the probability that the mean lifetime of these phones
will be less than 23.2 months. Assume cell phone life is a normally distributed variable, the sample is taken from a large
population and the correction factor can be ignored. Round the final answer to at least four decimal places and intermediate
z-value calculations to two decimal places.
P(X < 23.2) =?