Chapter 2.
Which two graphs allow the reader to retrieve the original list of data?
Stem-and-leaf plots and dotplots
Which of the following is not a difference between bar charts and histograms?
A bar chart is used for numerical variables while a histogram is used for categorical variables.
A categorical variable is only called bimodal under what circumstances?
Two categories are nearly tied for most frequent outcomes.
Suppose that you have data which indicates that 90% of adults in a nearby town have cell phones. Of those who have cell phones, 30% use Carrier A, 30% use Carrier B, 10% use Carrier C, 20% use Carrier D, 5% use Carrier E, and 5% use other carriers. Which of the following is not a reasonable graph to display this information?
histogram
A(n) ____________________ is a bar graph in which the height of each rectangle is the frequency or relative frequency of the class. The width of each rectangle is the same, and the rectangles touch each other.
histogram
After constructing any relative frequency distribution, what should be the sum of the relative frequencies?
1 or 100%
When describing the distribution of a categorical variable, the category that appears most often is called the
mode.
A frequency distribution lists the _________ of occurrences of each category of data, while a relative frequency distribution lists the _________ of occurrences of each category of data.
number proportion
Explain the difference between a bar graph and a Pareto chart.
A Pareto chart is a particular type of bar graph in which the bars are drawn in decreasing order of height.
Identify which of these methods can be used to distort a bar graph.
A.making the width of the bars proportional to their height B. stretching the vertical scale C.starting the vertical axis at a point other than the origin
What is an advantage to using a stem-and-leaf plot instead of a histogram to display data?
A stem-and-leaf plot allows for retrieval of the original data from the plot while the histogram does not.
Which of the following is not a valid point of comparison between histograms and bar graphs?
Histograms always have horizontal bars, while bar graphs can be either horizontal or vertical.
Suppose that you have data which indicates that 90% of adults in a nearby town have cell phones. Of those who have cell phones, 30% use Carrier A, 30% use Carrier B, 10% use Carrier C, 20% use Carrier D, 5% use Carrier E, and 5% use other carriers. Would a bar graph or pie chart be better if the goal is to compare Carrier B and Carrier C? Explain.
A bar graph would be better since you are trying to compare two parts, not a part to the whole. The angles might be difficult to judge on a pie chart, making it hard to directly compare two sectors.
What are Pareto charts?
Bar charts that are sorted from most frequent to least frequent
What are two commonly used graphs to display the distribution of a sample of categorical data?
Bar graph and pie chart
What is the most common trick to mislead readers of bar graphs?
Change the scale of the vertical axis so that it does not start at 0.
What is the first step in almost every investigation of data?
Make an appropriate graph.
Which information can you obtain from a stem-and-leaf plot but not from a histogram?
Minimum and maximum data values
When summarizing graphs of categorical data, report the _____________ and describe the ________________
Mode(s) variability
Because the human eye has a difficult time judging how much area is taken up by the wedge-shaped slice of a pie chart, which of the following is true of pie charts?
Pie charts are not commonly used by statisticians or in scientific settings.
True or false? A histogram and a relative frequency histogram, constructed from the same data, always have the same basic shape.
True. A relative frequency histogram will have a different scale on the y-axis but the same shape as a regular histogram.
Suppose you want to know if more technical service calls are made to homes with cable television or with satellite dish television. Should you use frequencies or relative frequencies to make the comparison? Why?
Relative frequencies should be used since there is likely a difference in the number of users of cable and satellite television. If you make comparisons using frequencies, the results can be very misleading for different population sizes.
Which of the statements below is true concerning bar graphs?
The height of each bar represents the category's frequency or relative frequency.