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QUESTION:

he instructor wanted to "pass" anyone who scored above 69. What proportion of exams will have passing scores?

ANSWER:


.7734



Good job! Let the random variable X represent the score on the exam. We are given that X is normal with a mean of 75 and standard deviation of 8, and need to find P(X < 69). 

Formula for probability, P(X is greater than 69) = P(Z greater than 69-75 divided by 8. This becomes P(Z greater than negative 0.75 equals 1 minus P(Z less than negative 0.75 equals .2266, which equals 1 minus .2266 and that equals .7734.


Posted by Cleveland on September 22, 2024
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