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Assume that 75 was the mean test score on an exam, with a standard deviation of 4 points. What percent had scores between 67 and 75? U
Question
Assume that 75 was the mean test score on an exam, with a standard deviation of 4 points.
What percent had scores between 67 and 75? Use the % symbol in your answer.
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Mathematics
3 years
2021-08-25T05:58:57+00:00
2021-08-25T05:58:57+00:00 1 Answers
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Answer:
68%
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
Approximately 68% of the measures are within 1 standard deviation of the mean.
Approximately 95% of the measures are within 2 standard deviations of the mean.
Approximately 99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean of 75, standard deviation of 4.
What percent had scores between 67 and 75?
67 = 71 – 4
75 = 71 + 4
Within 1 standard deviation of the mean, so, by the Empirical Rule, 68%.