Chapter 2
Which of the following are characteristics of frequency distributions?
- it provides the tally for each class - use classes and frequencies to organize data - organize raw data
A frequency polygon shows the shape of a distribution and is similar to:
histogram
What does the rule "2 to the k rule" mean
k is the smaller number in which case 2^k is greater than n
Which of the following are characteristics of bar charts?
- bar charts are used for qualitative data - plotted rectangles should be the same width - there should be gaps between bars
Which of the following can be observed from a histogram?
- concentration of the data - shape of the distribution - the approximate number of observations - the spread of the data
In a frequency polygon the points are plotted at the intersection of the class frequencies and the:
class midpoints
Which one of the following is true regarding raw data?
raw data are simply a listing of data before summarizing it
Which of the following are characteristics of a frequency table?
- no observation can fit into more than one class - they can be used for qualitative data
Regarding frequency tables and frequency distributions, which of the following are true?
- only frequency tables use qualitative data - both use mutually exclusive classes
Which of the following are characteristics of raw data?
- raw data can be either qualitative or quantitative - when the data is in its original form it is referred to as raw data
Which of the following practices are commonly used in setting class limits for a frequency distribution?
- rounding the class size up - placing "excess" interval width equally in the two tails of the distribution
Which of the following best describes a frequency table?
A grouping of qualitative data into classes showing the number of observations in each class
To divide data with a high value of H and a low value of L into k classes, the class interval must be:
at least (H-L)/k
The value shown on the vertical axis of a cumulative frequency polygon for a particular class is found by:
counting the number of observations less than the upper limit of the class
Which of the following is not a useful practice in setting individual class limits for a frequency distribution?
excluding outliers that cause the interval to be too wide
The number of observations in each class is called the class _____
frequency
A relative frequency distribution shows:
the fraction or percentage of observations in each class interval
Which of the following features is not part of a histogram?
the frequency of occurrence of a nominal variable
What information is shown on the horizontal axis of a bar chart?
the qualitative class labels
Which of the following operations is true regarding relative frequency distributions?
the relative frequency is found by dividing the class frequencies by the total number of observations
Which of the following is the best definition of "class midpoint"?
halfway between the lower or upper limits of two consecutive classes
Which of the following features is an advantage that the frequency polygon has over the histogram?
it can directly compare two or more frequency distributions
Which of the following is an advantage of a cumulative frequency polygon over a histogram or frequency polygon?
it can show the total number of observations less than a particular class' upper limit
Which of the following is not a characteristic of a frequency distribution?
it summarizes qualitative data
A frequency distribution table shows the number of observations for each class interval of data. How is this data plotted as a frequency polygon?
Frequency is plotted on the vertical axis and the class midpoint is plotted on the horizontal axis
Which of the following is a feature of a relative frequency distribution?
the same of the relative frequencies must be one (assuming no rounding errors)
