1. Which of the following is not a valid description of an outlier?

A. A data value beyond the outer fences.

B. A data value that is very unusual.

C. A data value that lies below Q1 or above Q3.

D. A data value several standard deviations from the mean.

2. In a sample of 10,000 observations from a normal population, how many would you expect to lie beyond three standard deviations of the mean?

A. None of them.

B. About 27.

C. About 100.

D. About 127.

3. Exam scores in a small class were 10, 10, 20, 20, 40, 60, 80, 80, 90, 100, 100. For this data set, which statement is incorrect concerning dispersion and shape?

A. The coefficient of variation is 65.7%.

B. The data are left-skewed due to low outliers.

C. The midrange and mean are almost the same.

D. The third quartile is approximately 90.

4. Twelve randomly-chosen students were asked how many times they had missed class during a certain semester, with this result: 3, 2, 1, 2, 1, 5, 9, 1, 2, 3, 3, 10. The standard deviation is

A. 2.90

B. 3.03

C. 2.55

D. 2.47

5. Which is not an advantage of the method of medians to find Q1 and Q3?

A. Ease of interpolating quartile positions.

B. Ease of application in small data sets.

C. Intuitive definitions without complex formulas.

D. Same method as Excel's = QUARTILE function.

6. Which is not a characteristic of the standard deviation?

A. It is always the square root of the variance.

B. It is not applicable when data are continuous.

C. It can be calculated when the data contain negative or zero values.

D. Its physical interpretation is not as easy as the MAD.

7. If samples are from a normal distribution with = 100 and = 10 we do not expect

A. about 68 percent of the data within 90 to 110.

B. almost all the data within 70 to 130.

C. about 95 percent of the data within 80 to 120.

D. about half the data to exceed 60.

8. The Excel formula for the standard deviation of a sample array named Data is

A. =STDEV(Data)

B. =STANDEV(Data)

C. =STDEVP(Data)

D. =SUM(Data)/(COUNT(Data) - 1)

9. Exam scores in a small class were 10, 10, 20, 20, 40, 60, 80, 80, 90, 100, 100. For this data set, which statement is incorrect concerning central tendency?

A. The median is 60.00.

B. The mode is not helpful.

C. The 5% trimmed mean would be awkward.

D. The geometric mean is 35.05.

10. A population consists of the following data: 7, 11, 12, 18, 20, 22, 25. The population variance is

A. 6.07

B. 36.82

C. 5.16

D. 22.86

11. In the following data set {7, 5, 0, 2, 7, 15, 5, 2, 7, 18, 7, 3, 0} the value 7 is

A. the mean.

B. the mode.

C. both the mode and median.

D. both the mean and mode.

12. The median of 600, 800, 1000, 1200 is

A. 800.

B. 1000.

C. 900.

D. 950.

13. Three randomly-chosen Colorado students were asked how many times they went rock climbing last month. Their replies were 5, 6, 7. The standard deviation is

A. 1.212

B. 0.816

C. 1.000

D. 1.056