A survey found that people keep their televisions an average

A survey found that people keep their televisions an average of 4.4 years. The standard deviation is 0.73 year. If a person decides to buy a new TV, find the probability that he or she owned the old one for the given amount of time. Assume the random variable is normally distributed.

Solution

here for the given time means = 4.4 years

hear mean = 4.4 and s.d = 0.73

For x = 4.4, the z-value z = (4.4 - 4.4) / 0.73 = 0

Hence P(x < 4.4) = P(z < 0) = [area to the left of 0] = 0.50