PLS 209                                                                                 Name___________________________
Research Methods
Homework6
Confidence Interval Using SPSS 

       COMPUTER INSTRUCTIONS

In carrying out the following instructions use the examples in your handout  titled "Computer Procedures for Using Political Science Data Sets."

    Step 1 Open PD83NS in SPSS

• From the PLS 209 homepage Go to the SPSS Download Page
• On the SPSS download page click-on PD83NS -- this is the Nation States under the International and Comparative Section
• Follow the directions on the download page for unzipping the file and opening it in SPSS

  Step 2 Use SPSS to generate descriptive statistics

• From the Data Editor Window select the Analyze Menu
• Select Descriptive Statistics on the Analyze Menu 
• Select Descriptives   
• Highlight the following variables and move them to the right window:  
      urban           "Percent of population in urban areas, 2000"
     gdp98           "Total GDP of country in missions of dollars, 1998"
     literacy        "Literacy as percent of total population, various years"
     rich 10         "Richest 10% share of income or consumptions (%), various years"
• Click on the Options Button
• Make sure mean,  std deviation, and S.E. of mean are checked 
• Click Continue
• Click OK

    Step 3 Print the table in the output window 

The table should contain the mean and standard error of the mean for each variable.

  QUESTIONS

    Once you have the printed output, do the following on the printed output.

      (1) Construct 95% confidence intervals for variables urban and gdp98
           CI = mean +/- (1.96*SE)   [SE=standard error and is on the output]

      (2) Construct two confidence intervals for literacy
          [Make sure you use the appropriate Z value for both a. and b.]
             a. The first is a 90% confidence interval
             b. The second is a 99% confidence interval

      (3) Construct two confidence intervals for rich10
             a. The first is a 95% confidence interval using the displayed SE
             b. The second is a 95% confidence interval using one half the displayed SE

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