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# MCQs: Empirical rule of Normal Distribution

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If the mean and the standard deviation of a continuous random variable that is normally distributed are 20 and 5, respectively, find an interval that contains 68% of the distribution.

A. (18,24)
B. (15,25)
C. (12,25)
D. (10,30)

2. If the mean and the standard deviation of a continuous random variable that is normally distributed are 28 and 3 respectively, find an interval that contains 95% of the distribution.

A. (22,34)
B. (25,31)
C. (20,35)
D. (19,37)

3 A competency test has scores with a mean of 80 and a standard deviation of 10. A histogram of the data shows that the distribution is normal. Use the Empirical Rule to find the percentage of scores between 70 and 90.

A. 99.7%
B. 95%
C. 68%
D. 50%

4. The heights of adult women are normally distributed with a mean of 62.5 inches and standard deviation of 2.5 inches. Use the Empirical Rule to determine between what two heights 68% of adult women will fail.

A. (52.5,72.5)
B. (55,70)
C. (57.5,67.5)
D. (60,65)

5. The heights of adult women are normally distributed with a mean of 62.5 inches and standard deviation of 2.5 inches. Use the Empirical Rule to determine between what two heights 99.7% of adult women will fail.

A. (52.5,72.5)
B. (55,70)
C. (57.5,67.5)
D. (60, 65)