The scores on an exam are normally distributed, with a mean of 75 and a standard deviation of 5. what percent of the scores are less than 80?

a. 50%
b. 84%
c. 13.5%
d. 16%

B. 84%

Step-by-step explanation:

Given

Mean= π=75

Standard Deviation= σ=5

As we have to calculate the percentage of score less than 80, we will find the z-score of 80

z=(x-μ)/σ

=  (80-75)/5

=5/5

=1

The z-score table value for 1 is 0.8413.

For converting this value into percentage, the value will be multiplied by 100.

So,

Percentage of students whose score is less than 80 = 0.8413*100

=84.13%

Rounding off gives us : 84%

So option B is the correct answer..

1 is c

2 is a

3 is a

step-by-step explanation: