statistics
posted by yolanda .
the life expectancy of lung cancer patient treated with a new drug is normally distributed with a mean of 4 years and a standard deviation of 10 months what is the probability that a randomly selected lung cancer patient will last more than 5 years

Z = (x  μ)/SD (converted to years)
Z = (5 4)/SD (converted to years)
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion higher than that Z score.