For Exercise 12.1, see page xxx; for Exercise 12.2, see page xxx; for Exercise 12.3, see page xxx.
12.4 Mean. The mean of the three numbers, 1, 2, and 9 is equal to
(a) 2.
(b) 4.
(c) 5.
(d) 6.
12.5 Standard deviation. Which of the following statements is true of the standard deviation?
(a) It measures the variability of a set of data.
(b) It can be strongly affected by outliers.
(c) It is best used as a measure of variability for roughly symmetric distributiuons.
(d) All of the above.
12.6 Median. Which of the following is true of the median of a set of observations?
(a) It must be larger than the mean of the observations.
(b) It must be smaller than the mean of the observations.
(c) It is the midpoint of the observations.
(d) It describes the variability of the observations.
12.7 The five-number summary. Which of the following is a graph of the five-number summary?
(a) A histogram.
(b) A stemplot.
(c) A boxplot.
(d) A bar graph.
12.8 Describing distributions. Which of the following should you use to describe a distribution that is skewed?
(a) The five-number summary.
(b) The mean, the first quartile, and the third quartile.
(c) The mean and standard deviation.
(d) The median and standard deviation.