Question

A set of mathematics exam scores are normally distributed with a mean of 80.280.280, point, 2 points and a standard deviation of 444 points. What proportion of exam scores are between 828282 and 85.685.685, point, 6 points? You may round your answer to four decimal places.

Answer 1

Answer:

0.3745

Step-by-step explanation:

Data

mean ($\mu$): 80

standard deviation ($\sigma$): 4

Normal distribution table is in figure attached .

$Z = \frac{x - \mu}{\sigma }$

Z = (85 - 80)/4 = 1.25

Area below curve = 0.3944

Z = (82 - 80)/4 = 0.5

Area below curve = 0.0199

Proportion of exam scores between 82 and 85?

0.3944 - 0.0199 = 0.3745

Answer 2

Answer: 0.3330 is right

Step-by-step explanation: