Frequency Distributions and Descriptive Statistics in SPS

Transcription

1 230 Combs Building studentcomputing.eku.edu Frequency Distributions and Descriptive Statistics in SPSS In this tutorial, we re going to work through a sample problem and construct frequency distributions and view some basic descriptive statistics. We will then generate a histogram based on the results. Sample Problem: Ten men and ten women participated in a three point shootout basketball competition. Each participant got 10 attempts. Their scores reflect the number of 3 point shots made out of 10. We re interested in the variables gender and shots made, although for this tutorial gender won t be affecting the data. For gender: 1 represents male and 2 represents female. Participant Gender Shots_made Fall 2013 Frequency Distributions and Descriptive Statistics in SPS

2 So, as you can see we need three variables (columns). In order to set up three different variables, open SPSS and click on the Variable View tab located in the bottom left corner, next to the Data View tab. The Data View tab is automatically selected when you first open SPSS. This will change your view where each row will represent a variable. Here you can name the variables and make any other changes that are necessary. The only thing we re going to change is the name for each variable and the number of decimals; each variable will need to be changed to 0 in the drop down menu in the decimal column. Once entered, the variables on your variable view should look like the above picture. If everything is entered correctly, navigate back to the Data View by clicking on the tab in the bottom left corner. *If you want the values for 1 and 2 in the Gender variable to be displayed with their corresponding category in the output (1 for male, 2 for female) then you can do this by clicking on the Value cell in the Gender column. A button will appear that contains Click this button to open another dialog box. Here you can assign labels to certain values. Simple put 1 in the Value box and Male in the Label and click Add. Repeat with the appropriate information for the female label, then click OK.

3 If your variables are set up correctly then you can go ahead and enter the data presented on the first page of this tutorial. Once entered, your spreadsheet should look like the image to the left. Now, we re ready to construct the frequency distribution and obtain some basic descriptive statistics. You ll need click Analyze > Descriptives Statistics > Frequencies

4 Once you click Descriptives, the following dialog box will pop up: Initially, all variables will appear in the left side. You will need to click on Gender and then click the center arrow to move it to the right side (Variables box). Both Gender and Shots_made need to be in the right box, just like the image above. Once you ve added both variables to the right side, click on the Statistics button located in the upper right corner.

5 Initially, all boxes will be unchecked. You will need to manually check all of the boxes that are checked in the image to the left. Once you have completed this, you can click the Continue button. This will close the dialog box and you will be back at the Frequencies dialog box. Now click on the Charts button located on the right side. Once here, you will want to select the button next to Histograms. You can then hit Continue to close the Charts dialog box and then Continue on the main Frequencies dialog box to compute the statistics.

6 This is one of the outputs you will see once SPSS runs the frequencies and descriptives. In the Shots_made column, you can see the mean, median, and mode for the number of shots made as well as other descriptive statistics like standard deviation, range, and minimum and maximum shots made.

7 Here we have the frequency table. The Gender table is self explanatory and isn t of any use to us. The Shots_made table indicates the frequency for each number of shots made. Percentages and cumulative percentages have also been calculated.

8 This is the frequency histogram for the Shots_made column. SPSS will also print a gender histogram but it s not very useful so I didn t include it in the tutorial. For this type of data, you could ve also used a bar graph because the range of numbers isn t very large, but this histogram also works just fine. We can see the frequency of each individual number of shots in graphic form. And this concludes the tutorial for simple frequencies and descriptives in SPSS.