Q:

A study was done to determine the stress levels that students have while taking exams. The stress level was found to be normally distributed with a mean stress level of 8.2 and a standard deviation of 1.34. What is the probability that at your next exam, you will have a stress level between 9 and 10?

Accepted Solution

A:
Answer: 0.1841Step-by-step explanation:Given: Mean : [tex]\mu=8.2[/tex]Standard deviation : [tex]\sigma = 1.34[/tex]The formula to calculate z-score is given by :_[tex]z=\dfrac{x-\mu}{\sigma}[/tex]For x= 9, we have[tex]z=\dfrac{9-8.2}{1.34}\approx0.60[/tex]For x= 10, we have[tex]z=\dfrac{10-8.2}{1.34}\approx1.34[/tex]The P-value = [tex]P(0.6<z<1.34)=P(z<1.34)-P(z<0.6)[/tex][tex]=0.9098773-0.7257469=0.1841304\approx0.1841[/tex]Hence, the probability that at your next exam, you will have a stress level between 9 and 10 = 0.1841