# 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 **mean**, **standard deviation**, **minimum**, **maximum**, 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 Curve**button 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 **mean**, **standard deviation**, **minimum**, **maximum**, **S.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.