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

Step-by-step explanation:

Given: Mean : $\mu = 82$

Standard deviation : $\sigma = 13$

The formula to calculate z is given by :-

$z=\dfrac{x-\mu}{\sigma}$

For x= 80

$z=\dfrac{80-82}{13}=−0.15384615384\approx-1.5$

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