SOLUTION: Students grades were normally distributed with a mean of 73 and a standard deviation of 11. a. 7.93 percent of the students received grades of A. what is the minimum score needed

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Question 421339: Students grades were normally distributed with a mean of 73 and a standard deviation of 11.
a. 7.93 percent of the students received grades of A. what is the minimum score needed to receive a grade of A?
b. Students who made 57.93 or lower on the exam failed the course. What percent of students failed the course?
c. If 69.5 percent of the syudents received grades of C or better, what is the minimum score of those who received a C?
Answer by stanbon(75887) About Me  (Show Source):
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Students grades were normally distributed with a mean of 73 and a standard deviation of 11.
a. 7.93 percent of the students received grades of A. what is the minimum score needed to receive a grade of A?
Find the z-value with a right tail of 7.93%
invNorm(1-0.0793) = 1.4098
Find the corresponding x-value using x = zs+u
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x = 1.4098*11 + 73 = 88.51
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b. Students who made 57.93 or lower on the exam failed the course. What percent of students failed the course?
Same process as with part "a":
Find the z-value of 57.93
Find the corresponding x-value.
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c. If 69.5 percent of the syudents received grades of C or better, what is the minimum score of those who received a C?
Same process as with part "a" and part "b".
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Cheers,
stan H.