Lesson 4: Displaying Public Health Data
SelfAssessment Quiz
Now that you have read Lesson 4 and have completed the exercises, you should be ready to take the selfassessment quiz. This quiz is designed to help you assess how well you have learned the content of this lesson. You may refer to the lesson text whenever you are unsure of the answer.
Unless otherwise instructed, choose ALL correct choices for each question.

 Tables and graphs are important tools for which tasks of an epidemiologist?
 Data collection
 Data summarization (descriptive epidemiology)
 Data analysis
 Data presentation
 A table in a report or manuscript should include:
 Title
 Row and column labels
 Footnotes that explain abbreviations, symbols, exclusions
 Source of the data
 Explanation of the key findings
 Tables and graphs are important tools for which tasks of an epidemiologist?
 The following table is unacceptable because the percentages add up to 99.9% rather than 100.0%
The following table is unacceptable because the percentages add up to 99.9% rather than 100.0% Age group No. Percent < 1 year 10 19.6 1–4 9 17.6 5–9 9 17.6 10–14 17 33.3 ≥15 6 11.8 Total 53  True
 False
 In the following table, the total number of persons with the disease is:
In the following table, the total number of persons with the disease Cases Controls Total Total 25 25 50 Exposed 22 12 34 Unexposed 3 13 16  3
 22
 25
 34
 50
 A table shell is the:
 Box around the outside of a table
 Lines (“skeleton”) of a table without the labels or title
 Table with data but without the title, labels or data
 Table with labels and title but without the data
 The best time to create table shells is:
 Just before planning a study
 As part of planning the study
 Just after collecting the data
 Just before analyzing the data
 As part of analyzing the data
 Recommended methods for creating categories for continuous variables include:
 Basing the categories on the mean and standard deviation
 Dividing the data into categories with similar numbers of observations in each
 Dividing the range into equal class intervals
 Using categories that have been used in national surveillance summary reports
 Using the same categories as your population data are grouped
 In frequency distributions, observations with missing values should be excluded.
 True
 False
 The following are reasonable categories for a disease that mostly affects people over age 65 years:
Age Group
< 65 years
65–70
70–75
75–80
80–85
85 True
 False
 In general, before you create a graph to display data, you should put the data into a table.
 True
 False
 On an arithmeticscale line graph, the xaxis and yaxis each should:
 Begin at zero on each axis
 Have labels for the tick marks and each axis
 Use equal distances along the axis to represent equal quantities (although the quantities measured on each axis may differ)
 Use the same tick mark spacing on the two axes
 Use the following choices for Questions 12a–d:
 Arithmeticscale line graph
 Semilogarithmicscale line graph
 Both
 Neither
 ____ A wide range of values can be plotted and seen clearly, regardless of magnitude
 ____ A constant rate of change would be represented by a curved line
 ____ The yaxis tick labels could be 0.1, 1, 10, and 100
 ____ Can plot numbers or rates
 Use the following choices for Questions 13a–d:
 Histogram
 Bar chart
 Both
 Neither
 ____ Used for categorical variables on the xaxis
 ____ Columns can be subdivided with color or shading to show subgroups
 ____ Displays continuous data
 ____ Epidemic curve
 Which of the following shapes of a population pyramid is most consistent with a young population?
 Tall, narrow rectangle
 Short, wide rectangle
 Triangle base down
 Triangle base up
 A frequency polygon differs from a line graph because a frequency polygon:
 Displays a frequency distribution; a line graph plots data points
 Must be closed (plotted line much touch xaxis) at both ends
 Cannot be used to plot data over time
 Can show percentages on the yaxis; a line graph cannot
 Use the following choices for Questions 16a–d:
 Cumulative frequency curve
 Survival curve
 Both
 Neither
 ____ Yaxis shows percentages from 0% to 100%
 ____ Plotted curve usually begins in the upper left corner
 ____ Plotted curve usually begins in the lower left corner
 ____ Horizontal line drawn from 50% tick mark to plotted curve intersects at median
 A scatter diagram is the graph of choice for plotting:
 Anabolic steroid levels measured in both blood and urine among a group of athletes
 Mean cholesterol levels over time in a population
 Infant mortality rates by mean annual income among different countries
 Systolic blood pressure by eye color (brown, blue, green, other) measured in each person
 Which of the following requires more than one variable?
 Frequency distribution
 Onevariable table
 Pie chart
 Scatter diagram
 Simple bar chart
 Compared with a scatter diagram, a dot plot:
 Is another name for the same type of graph
 Differ because a scatter diagram plots two continuous variables; a dot plot plots one continuous and one categorical variable
 Differ because a scatter diagram plots one continuous and one categorical variable; a dot plot plots two continuous variables
 Plots location of cases on a map
 A spot map must reflect numbers; an area map must reflect rates.
 True
 False
 To display different rates on an area map using different colors, select different colors that have the same intensity, so as not to bias the audience.
 True
 False
 In an oral presentation, threedimensional pie charts and threedimensional columns in bar charts are desirable because they add visual interest to a slide.
 True
 False
 A 100% component bar chart shows the same data as a stacked bar chart. The key difference is in the units on the xaxis.
 True
 False
 When creating a bar chart, the decision to use vertical or horizontal bars is usually based on:
 The magnitude of the data being graphed and hence the scale of the axis
 Whether the data being graphed represent numbers or percentages
 Whether the creator is an epidemiologist (who almost always use vertical bars)
 Which looks better, such as whether the label fits below the bar
 Use the following choices for Questions 25a–d (match all that apply):
 Grouped bar chart
 Histogram
 Line graph
 Pie chart
 ____ Number of cases of dog bites over time
 ____ Number of cases of dog bites by age group (adult or child) and sex of the victim
 ____ Number of cases of dog bites by breed of the dog
 ____ Number of cases of dog bites per 100,000 population over time