Question

Use the following to answer question 39: The average score of 100 students taking a statistics final was 70 with a standard deviation of 7. Assuming a normal distribution, what is the probability that students scored less than 60

Answer 1

The probability of students scored less than 60 = .0768

Explanation:

Given -

Mean score
`(\\u )` = 70

standard deviation
`(\sigma )` = 7

Let X be the score of students

the probability that students scored less than 60 =

`P(X< 60)` =
`P((X - \\u )/(\sigma)< (60 - 70)/(7))`

=
`P(z < (60 - 70)/(7))` put[ Z=
`(X - \\u )/(\sigma)`]

=
`P(z < -1.428)` using z table

= .0768