Answer to Question #347186 in Statistics and Probability for Aiai

Question

If the average time spent studying is 10 hours and the standard deviation is 4 hours, what it the probability that a student will spend more than 13 hours studying?

Answer 1

$$P(X>13)=1-P(Z\le\dfrac{13-10}{4})$$

$$=1-P(Z\le0.75)\approx0.2266$$