C3

We create a frequency distribution for interval data by counting the number of observations that fall into each of a series of intervals, called ____________________.

classes

We determine the approximate width of the classes by subtracting the smallest observation from the largest and dividing the answer by the number of ____________________.

classes intervals

The relative frequency of a class in a histogram is computed by a. dividing the frequency of the class by the number of classes. b. dividing the frequency of the class by the class width. c. dividing the frequency of the class by the total of all frequencies. d.None of these choices.

C

Which of the following statements about histograms is true? a. A histogram is a summary of interval data. b. A histogram is made of a series of intervals, called classes. c. The classes in a histogram cover the complete range of observations. d. All of these choices are true.

D

What values are displayed on a cumulative relative frequency distribution? a. The number of observations that fall into each class interval. b. The proportion of observations that fall into each class interval. c. The number of observations that fall below each class interval. d. The proportion of observations that fall below each class interval.

D是below。B错在into

A skewed histogram is one with a long tail extending either to the right or left.

F

The sum of cumulative relative frequencies always equals 1

F

The more observations we have, the ____________________ the number of class intervals we need to use to draw a useful histogram.

larger higher greater

A(n) ____________________ is a graphical representation of the cumulative relative frequencies.

ogive