Question

The average number of calories in a 1.5-ounce chocolate bar is 217. Suppose that the distribution of calories is approximately normal with standard deviation is 9. Find the probability that a randomly selected chocolate bar will have more than 190.

Answer 1

$P(X>190)=P(Z>\frac{190-217}{9})=P(Z>-3)=P(Z<3)=0.9987.$