Question 1032019: The mean and standard deviation of 500 students who took a statistics final were 72 and 8, respectively. The grades have a mound-shape distribution. Based upon this information, the best estimate of the percentage of students who scored higher than 80 on the exam is
A 68%
B 32%
C 16%
D 5%
E 2.5%
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! The mean and standard deviation of 500 students who took a statistics final were 72 and 8, respectively. The grades have a mound-shape distribution. Based upon this information, the best estimate of the percentage of students who scored higher than 80 on the exam is
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(80-72)/8 = 1
That means a score of 80 is one standard deviation above the mean>
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Since 68% of the data is within 1 standard deviation of the mean,
34% is within 1 std to the right of the mean.
So 50% - 34% = 16% of the scores are higher than 80
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Cheers,
Stan H.
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A 68%
B 32%
C 16%
D 5%
E 2.5%
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