Question: A recent study of the lifetimes of cell phones found the average to be 24.3 months with a standard deviation of 2.6 months. Assume cell phone life is a normally distributed variable.

? Use Table 4 (Standard Normal probability table), software, or the TI-calculator to find the probability that the life of a single cell phone chosen at random will be less than 23.8 months.

? Use the Central Limit Theorem to find the probability that the sample mean cell phone life of a random sample of 33 cell phones will be less than 23.8 months.