## Examination 2

Directions:
Respond to each item in a clear and concise paragraph. (In some cases, a single sentence will suffice.) Do not copy passages from the lectures or book. Rather, express your own understanding of the material. Do not write anything or everything that comes to mind; instead, try to devise a brief answer that captures the most relevant information. Before you submit, make a note of the number in the first comment, below. You will need to input this number into the form to submit your work. (This is to prevent spammers from using the form. Sorry about that. Spammers ruin everything.)

Part I. Probability
Use the following frequency table to answer questions in part I. For questions in this part, explain your work.

 Nation f Spain 178 Germany 102 Italy 97 Brazil 214 Japan 160 China 148

1. What is the probability that you will select a person at random from this population who is from Spain?

2. What is the probability that you will select a person at random from this population who is from Asia?

3. What is the probability that you will select three people not from Europe?

Part II. Standard Scores
Suppose you have a population of 1,200 city agencies. The mean budget for these agencies is \$12.67 million. The standard deviation is \$22.9 million.

4. What is the likelihood that you could select a city agency at random that had a budget greater than \$35 million?

5. What is the likelihood that you could select a city agency at random that had a budget below \$10 million?

Suppose you have a population of 12,000 state legislators. The mean age is 58.8 years, with a standard deviation of 12.5 years.

6. What is the likelihood that you could select a legislator who is between the ages of 55 and 65?

Part III. The Sampling Distribution

7. In your own words, explain the sampling distribution and why it is significant.

8. What are the three important characteristics of the normal curve?

9. Why is the standard error of the sampling distribution always smaller than the standard deviation of the population?

Suppose that you have a population of campaign speeches from the 1980s. The mean number of references to "family values" in a speech is 6.73, with a standard deviation of 14.40.

10. What is the probability of drawing a random sample of 100 speeches with a mean of 7 or more references?

Part IV. Data Analysis

11. Select one numeric variable from one of our dataframes. Calculate a 95% confidence interval and interpret the results.

12. Select two binary variables from one of our dataframes. (You may select a categorical variable and recode it to binary.) Calculate the crosstabulation with odds and interpret the results.

13. Select a categorical variable and a numeric variable from one of our dataframes and perform the hypothesis test. Interpret the results.

14. Select two categorical independent variables and one numeric dependent variable from one of our dataframes and perform the hypothesis test. Interpret the results.

Part V. Articles

15. Summarize Table 1 in Stockard and O'Brien.

This question will not be graded. I should have moved this reading to the next section, on regression analysis. My mistake. 16. Summarize Table 4 in Langford and Mackinnon.

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