Question

The time to complete a standardized exam is approximately normal with a mean of 70 minutes and a standard deviation of 10 minus. Using the 68-95-99.7 rule, what percentage of students will complete the exam in under an hour?

Answer 1

Answer:

Step-by-step explanation:

Given that the  time to complete a standardized exam is approximately normal with a mean of 70 minutes and a standard deviation of 10 minutes.

P(completing exam before 1 hour)

= P(less than an hour) = P(X<60)

=P(Z<$\frac{60-70}{10} =-1$)

=0.5-0.34=0.16

i.e. 16% of students completed the standardized exam.