The purpose of this activity is to learn how to use software to calculate a confidence interval for the population proportion p (for a given level of confidence). Software is particularly useful when raw data are given rather than data summaries, which are what you would usually encounter in practice.

Background: The U.S. federal ban on assault weapons expired in September 2004, which meant that after 10 years (since the ban was instituted in 1994) there were certain types of guns that could be manufactured legally again. A poll asked a random sample of 1,200 eligible voters (among other questions) whether they were satisfied with the fact that the law had expired. The datafile linked below contains the results of this poll (Data were generated based on a poll conducted by NBC News/Wall Street Journal Poll). We would like to estimate p, the proportion of U.S. eligible voters who were satisfied with the expiration of the law, with a 95% confidence interval.

The dataset is available in Excel format (guns.xls) and in CSV format (guns.csv)

If you prefer to skip this process and just answer the questions, you can reveal the value needed to continue.

Learn By Doing
Question prompt


  1. The number of courses the student takes this semester:
  2. The student's height:
  3. The student's (exact) body temperature:
  4. The number of siblings the student has:
  5. The (exact) time the student spends doing school work during a week:
  6. The number of alcoholic beverages that the student drinks in a typical week:
A Choice 1
B Choice 2
C Choice 3
D Choice D
E Choice E
F Choice F
G Choice G
H Choice H
Our Answer Comments.