A study of hours devoted to a graduate course outside of classroom time generates a mean score of 90 with a standard deviation of 20. The mean age of the students was 31 with a standard deviation of 5 years. What is the relative dispersion of the two data sets?
A. 2.22%; 1.6%
B. 22.22%; 16.13%
C. 34.44%; 20%
D. Not calculable without additional data
Based on the empirical rules, what percent of the observations in a data set will lie beyond two standard deviations above the mean?
A. 2.5%
B. 5%
C. 68%
D. 95%
For a sample of engineers, the mean salary is \$95,000 with a standard deviation of \$30,000. The median value is \$80,000. What is the relative shape of the distribution and coefficient of skewness?
A. Negatively skewed; -1.00
B. Negatively skewed; 1.00
C. Positively skewed; 1.50
D. Positively skewed; 3.00
13 29 41 60 89
14 26 53 7 14
What is the first quartile?
A. 11.5
B. 13.75
C. 37
D. 50.75
Based on the information in the chart in #14 (above), what is the interquartile range?
A. 6
B. 39.5
C. 41
D. 44.25
Based on the information in the chart in #14 (above), what is the 90th percentile?
A. 9.9
B. 55.5
C. 86.1
D. 89

The interquartile range describes the
A. lower 50% of observations
b. lower 25% and upper 25% of observations.
c.middle 50% of observations.
d.upper 50% of observations
A survey of passengers on domestic flights revealed these miles:
Miles Flown Number of Passengers
100 up to 500 16
500 up to 900 41
900 up to 1,300 81
1,300 up to 1,700 11
1,700 up to 2,100 9
2,100 up to 2,500 6
What is the range (in miles)?
A. 2,499
B. 1,100
C. 2,400
D. 1,999
A box plot shows:
A. the mean and variance.
B. the relative symmetry of a distribution for a set of data.
C. the percentiles of a distribution.
D. the deciles of a distribution.
What statistics are needed to draw a box plot?
A. Minimum, maximum, median, first, and third quartiles
B. Median, mean, and standard deviation
C. A mean and a dispersion
D. A mean and a standard deviation