Question

A set of 200 test scores are normally distributed with a mean of 70 and a standard deviation of 5. Approximately how many students scored between a 60 and an 80

Answer 1

Answer:  About 191 students scored between a 60 and an 80.

Step-by-step explanation:

Given : A set of 200 test scores are normally distributed with a mean of 70 and a standard deviation of 5.

i.e. $\mu=70$ and $\sigma=5$

let x be the random variable that denotes the test scores.

Then, the probability that the students scored between a 60 and an 80 :

$P(60$

The number of students scored between a 60 and an 80 = 0.9544 x 200

= 190.88 ≈ 191

Hence , about 191 students scored between a 60 and an 80.