Question

The distribution of scores in a exam has a normal distribution with a mean of 82 and a standard deviation of 13. What is the probability that a randomly selected score was less than 80? Enter your answer using decimal notation (and not percentages), and round your result to 2 significant places after the decimal (for example the probability of 0.1877 should be entered as 0.19)

Answer 1

Answer: 0.07

Explanation:

Given: Mean :
`\mu = 82`

Standard deviation :
`\sigma = 13`

The formula to calculate z is given by :-

`z=(x-\mu)/(\sigma)`

For x= 80

`z=(80-82)/(13)=−0.15384615384\approx-1.5`

The P Value =
`P(z<-1.5)=0.0668072\approx0.07`

Hence, the probability that a randomly selected score was less than 80 =0.07