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# Statistics, standard deviation, population, distribution

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12. In a statistic class, 10 scores were randomly selected with the following results were obtained (mean=71.5): 74, 73, 77, 77, 71, 68, 65, 77, 67, 66. What is the standard deviation?

A. 22.72
B. 12.00
C. 4.77
D. 516.20
E. 144.00

13. According to a survey of the top 10 employers in a major city in the Midwest, a worker spends an average of 413 minutes a day on the job. Suppose the standard deviation is 26.8 minutes and the time spent is approximately a normal distribution. What are the times that approximately 95.44% of all workers will fall?

A. [387.5 438.5]
B. [386.2 439.8]
C. [372.8 453.2]
D. [359.4 466.6]
E. [332.6 493.4]

14. If a population distribution is skewed to the left, then, given a random sample from that population, one would expect that the:

A. Mean would be greater than the Median
B. Median would be greater than the Mean
C. Median would be equal to the mean
D. Cannot tell without looking at the Histogram

15. When using the Chebyshev's theorem to obtain the bounds for a 99.73 percent of the values in a population, the interval generally will be ___________ the interval obtained for the same percentage if normal distribution is assumed (empirical rule).

A. Shorter than
B. Wider than
C. The same as
D. A Subset of

16. In a hearing test, subjects estimate the loudness (in decibels) of sound and the results are:
68, 67, 70, 71, 67, 75, 69, 62, 80, 73, 68 What is the median?
A. 67
B. 70
C. 68
D. 69
E. 80

17. The numbers of rooms for 15 homes recently sold were (mean=7.4): 8, 8, 8, 5, 9, 8, 7, 6, 6, 7, 7, 7, 7, 9, 9 What is the variance?
A. 1.96
B. 1.40
C. 4.00
D. 16.00
E 1.183