Complete the graphs as described in the worksheet.

EXTRA CREDIT Graphing exercises (up to 100 points)

Name___________________

1. Make a Histogram. (20 pts)

This table shows the number of new HIV diagnoses

during 2015, separated by age group. The data is

an example of Continuous Data as described on

p. 1 of the ‘Using Graphs and Charts” handout. A good way to visualize continuous data is to graph it in a histogram.

1a. Using the graph below, graph this data into a histogram. In this case, you will compare the difference in HIV incidences across various age groups.

Age (Years)

Number of Diagnoses

of HIV Infection, 2015

Under 13

120

13-14

25

15-19

1,628

20-24

7,084

25-29

7,510

30-34

5,437

35-39

4,194

40-44

3,418

45-49

3,302

50-54

3,010

55-59

1,860

60-64

996

65 or older

859

Divide the markers on the y-axis to 2000 cases per dividing line. (Ignore the numbers (0,1,2,3,4) and write in the numbers (0,2,4,6,8)

Draw a bar for each age group to the height that corresponds to the number of new cases for each age group.

Practice here:

Draw your final graph here.

1b. Now analyze your graph. A histogram allows you to visualize trends over time. Look at your completed histogram. What is the most interesting bit of data that you discovered?

2. Make a pie chart (20 pts)

2. CDC classifies HIV diagnoses into six transmission categories to which transmission may be attributed: male-to-male sexual contact, injection drug use, male-to-male sexual contact and injection drug use, heterosexual contact, mother-to-child (perinatal) transmission, and other (includes blood transfusions and unknown cause).

Following is the distribution of the number of diagnoses of HIV infection in 2015 among adults and adolescents in the United States, by transmission category. A breakdown by sex is provided, where appropriate. Since each of these data points falls into a separate category, this can be described as “categorical data” as described on p.1 of the worksheet.

Transmission Category	Adult and Adolescent Males	Adult and Adolescent Females	Total
Male-to-male sexual contact	26,375	NA	26,375
Injection drug use	1,412	980	2,392
Male-to-male sexual contact and injection drug use	1,202	NA	1,202
Heterosexual contact -a	2,948	6,391	9,339
Other -b	53	31	84

a- Heterosexual contact with a person known to have, or to be at high risk for, HIV infection.

b- Includes hemophilia, blood transfusion, perinatal exposure, and risk factor not reported or not identified.

Make two pie charts to display this data, one for Males and one for Females.

To make a pie chart,

First total up the data for each column (males or females). For example, calculate the sum of all adult and adolescent males diagnosed in 2015. (Use a calculator) = 31,990

Calculate the percentage of the total for each category. Example, Injection drug users among males = 1,202/ 31,190 = 0.0375. To convert that to percentage, multiply 0.0375 times 100 = 3.75%

You will have a different percentage for each category, but they should total up to 100% for that column. A circle can be divided into 360 degrees. To display that in a pie chart, you will need to calculate how many degrees are occupied by each category. In the example above, the figure out how a large a piece of the pie would be occupied by injection drug users, multiply 0.0375 times 360. If you have a protractor, you can divide the pie chart up proportionately. OR you could estimate. OR you could use a graphing program like Excel, Numbers or something that you find on the internet. For this exercise, estimating is fine.

Draw your graphs on the following page.

Now analyze your graphs. What is the most interesting bit of data that you discovered?

3. Extra credit assignment to accompany the Epidemiology Assignment 5 in Module 6.

(30 pts)

If you take a look at an Excel program, you will notice that under the heading of charts you will see more than a dozen types of charts available. If you have an excel program available, and you know how to plot data, you can type some data into to a worksheet page to recreate one of the data sets shown in the CDC Manual. For example, type the data in from Table 4.1a Reported Cases of Primary and Secondary Syphilis by Age — United States, 2002, just as it is displayed.You will have two columns. You can make a bar graph. Designate the age brackets to be along the x-axis, and the frequency, or number of cases, along the as the y-axis. Practice adding labels to the data.

Table 4.1a Reported Cases of Primary and Secondary Syphilis by Age — United States, 2002

Age Group (years)	Number of Cases
≤14	21
15–19	351
20–24	842
25–29	895
30–34	1,097
35–39	1,367
40–44	1,023
45–54	982
≥55	284
Total	6,862

Data Source: Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2002. Atlanta: U.S. Department of Health and Human Services; 2003.

4. Extra credit assignment to accompany the Epidemiology Assignment 5 in Module 6.

(30 pts)

If you want to try something more complex, you can add some variables to your table. Type the gender data from Table 4.2 Reported Cases of Primary and Secondary Syphilis by Age and Sex — United States, 2002 into your worksheet, and add those to your bar graph. You will get a bar graph similar to the graphs in Figure 6-1 on p.108 of your textbook.

This is not a required exercise, but you will receive extra credit if you do it.

Table 4.2 Reported Cases of Primary and Secondary Syphilis by Age and Sex — United States, 2002

	NUMBER OF CASES
Age Group (years)	Male	Female	Total
≤14	9	12	21
15–19	135	216	351
20–24	533	309	842
25–29	668	227	895
30–34	877	220	1,097
35–39	1,121	246	1,367
40–44	845	178	1,023
45–54	825	157	982
≥55	255	29	284
Total	5,268	1,594	6,862

Data Source: Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2002. Atlanta: U.S. Department of Health and Human Services; 2003.

Histogram

Age Groups

< 13 13-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 > 65

New HIV cases

Histogram

Age Groups

< 13 13-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 > 65

New HIV cases