The time needed to complete a final examination in a particular college course is normally distributed with a mean of 79 minutes and a standard deviation of 8 minutes. Answer the following questions.

A) 0.0088

B) 0.2997

C) 5

Step-by-step explanation:

Given: Mean: Ч = 79 minutes

Standard deviation : б = 8 minutes

The formula for z score:

z= x-ц/σ

a) For x=60 minutes

z= 60-79/8 = -2.375

The p-value = P(z< -2.375) = 0.0087745 ≈ 0.0088

b) For x= 75 minutes

z= 75-79/8 = -0.5

The p-value = P(60 < x < 75) = P (-2.375 < z < -0.5)

= P(-0.5)-P(-2.375)= 0.3085 -0.0088 =0.2997

c) For x=90 minutes

z= 90-79/8 = 1.375

The p-value = P (z > 1.375)= 1-P(z < 1.375)

= 1-0.9154342 = 0.0845658

If the number of students in the class=60.

Then, the number of students will be unable to complete the exam in the alotted time = 0.0845658 x 60 = 5.073948 ≈ 5