Descriptive Statistics

Descriptive Statistics

Using the Polit2SetA data set, run descriptive statistics on the following variables: respondent’s age (age) and highest school grade completed (higrade). Create a frequency distribution for the variables: race and ethnicity (racethn) and currently employed (worknow). Create a table (in APA format) summarizing the results, using the below table shell as a model. Write a paragraph summarizing the information in the table.

Table 1. Demographic Data (N = 30)

n % M (SD)

Age (in years) 30 15(2.4)

Highest School Grade Completed 29 11(1.2)

Race and Ethnicity

Black, Not Hispanic 14 (46.67)

Hispanic 8 (26.67)

White, Not Hispanic 6 (20.0)

Other 2 (6.66)

Currently Employed

Yes 27 (90)

No 3 (10)

Note. Differences in sample size are due to missing data.

Follow these steps when using SPSS:

1. Open Polit2SetA data set.

2. Click on Analyze, then click on Descriptives Statistics, then Descriptives.

3. Click on the first continuous variable you wish to obtain descriptives for (respondent’s age), and then click on the arrow button and move it into the Variables box. Then click on highest school grade completed and then click on the arrow button and move it into the Variables box.

4. Click on the Options button in the upper-right corner. Click on meanstandard deviationminimummaximum, and skewness.

5. Click on Continue and then click on OK.

To run the frequency distribution in SPSS, do the following:

1. Click on Analyze, then click on Descriptive Statistics, then Frequencies.

2. Click on the first categorical variable you wish to obtain a frequency for (race and ethnicity), and then click on the arrow button and move it into the Variables box. Then click on currently employed, and then click on the arrow button and move it into the Variables box. Click on the Statistics button in the upper-right corner, then in the Dispersion box click on Minimum and Maximum.

3. Click on Continue and then click on OK.

Assignment: Create a table (in APA format) summarizing the results, using the below table shell as a model. Write a paragraph summarizing the information in the table.

Part II

For the variables respondent’s age (age) and highest school grade completed (higrade) create a histogram with a normal curve displayed over the histogram.

To create a histogram for respondent’s age in SPSS, do the following:

1. Click on Graphs, then on Legacy Dialogs, then Histogram.

2. Click on the variable respondent’s age and then click on the arrow button and move it into the Variables box. Click on the Display Normal Curve button, which is right below the Variables box.

3. Click on OK.

To create a histogram for highest school grade completed in SPSS, do the following:

1. Click on Graphs, then on Legacy Dialogs, then Histogram.

2. Click on respondent’s age in the Variable box and click the arrow to move it back to the box on the left that contains all the variables.

3. Click on the variable highest school grade completed and then click the arrow button and move it into the Variables box. The Display Normal Curvebutton should alredy be on.

4. Click on OK.

Assignment: Using the data obtained when you ran the descriptives and the histograms, determine whether the data skewed. If so, is it a positive or negative skew?

Part III

Using the Polit2SetA data set, run descriptive statistics on the variable “Family Income Prior Month, all sources” (Income).

Follow these steps when using SPSS:

1. Click on Analyze, then click on Descriptives Statistics, then Descriptives.

2. Click on Family Income Prior Month, all sources, and then click on the arrow button and move it into the Variables box.

3. Click on the Options button in the upper-right corner. Click on meanstandard deviationminimummaximumS.E. Mean (standard error of the mean), and skewness.

4. Click on Continue and then click on OK.

Assignment: Using the descriptive statistics for Family Income Prior Month, all sources (Income), answer the following questions:

1. What is the mean income in this sample?

2. What is the standard deviation?

3. What is the standard error of the mean?

4. Compute a 95% confidence interval around the mean. (Use 1.96 for the 95% CI and get the standard error from the descriptive statistics table). The formula is as follows:

95% CI = [mean ± (1.96 SE)]

5. Compute a 99% confidence interval around the mean. (Use 2.58 for the 99% CI and get the standard error from the descriptive statistics table). The formula is as follows:

99% CI = [mean ± (2.58 SE)]

6. Which interval is wider? Explain.

Review the corresponding Week 4 Descriptive Statistics Exercises SPSS Output document that has the SPSS output for the above problems. Compare your output with the output in the file.


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