1. Using, Understanding, and Presenting Data Effectively
Got Data?
Using, Understanding, and Presenting Data Effectively

2. What question do you want to answer?
Country
Number of Credit Cards A
100 million B
200 million C
400 million
Which country has more credit cards?

3. What question do you want to answer?
Country
Population
Number of Credit Cards per Capita A
200 million .5 B
1.5 C
400 million
1.0
Which country has more credit cards per capita?
Wong, D. M. (2010). The Wall Street Journal guide to information graphics New York, NY. W.W. Norton & Company, p. 23

4. Good Polls are clearly worded
34%
Possible
66%
Impossible

5. Good polls are clearly worded9%
Doubtful 4%
Uncertain
87%
Not Doubtful
Bishop, G.F. (2005). The illusion of public opinion: Fact and artifact in American public opinion polls. Lanham, MD: Rowman and Littlefield

6. Good polls use random selection
In its August 22, 1936 issue, the Litereary Digest announced:
Once again, [we are] asking more than ten million voters -- one out of four, representing every county in the United States -- to settle November's election in October.
Poll Predictions: Landon 57% v. Roosevelt 43%
Poll Results (57% Landon 62% RooseveltFor the 1936 election, the Literary Digest prediction was that Landon would get 57% of the vote against Roosevelt's 43% (these are the statistics that the poll measured). The actual results of the election were 62% for Roosevelt against 38% for Landon
Squire, P. (1988). Why the 1936 Literary Digest poll failed. The Public Opinion Quarterly, 52, p

7. Good Polls minimize sampling error
20%
Product A
80%
Product B