Prison Sentences The average prison sentence for a person convicted of second-degree murder is 15 years. If the sentences are normally distributed with a standard deviation of 2.1 years, find the following probabilities. Round the final answers to at least four decimal places and intermediate z-value calculations to two decimal places. Part: 0 / 2 Part 1 of 2 (a) A prison sentence is greater than 18 years. P(X>18) = ==