Frequencies uses one of these methods, HAVERAGE, while Custom Tables uses the AEMPIRICAL method. The Explore procedure (Analyze-Descriptive Statistics->Explore EXAMINE command) offers five options for computing percentiles. Note that there are multiple methods for computing percentiles, including medians. The command equivalents for the steps outlined above are as follows. Furthermore, the actual interval covered by these limits is slightly larger than the desired 95% confidence interval it is in fact 95.2%, as identified by the entry reporting the Actual Coverage. The results will show you that the median is 28875, with a lower 95% confidence limit of 27750 and an upper 95% confidence limit of 30000. (Note that the default is for the 95% confidence interval, but you can modify the value in the subdialog box.) In the Statistics subdialog box, under Central Tendency, select Median and select Confidence Intervals. Similarly, highlight the variable UNIT and move it to the box labeled Denominator.Ĩ. In the Ratio Statistics dialog box, highlight the variable SALARY and click on the arrow to move it to the box labeled Numerator.Ħ. In the menus, go to Analyze->Descriptive Statistics->Ratio.ĥ. In the box labeled Numeric Expression, simply type the number 1 and then click OK.Ĥ. In this example, we'll call the variable UNIT.ģ. In the Compute Variable dialog box, type in any name that helps you remember that the new column will simply hold a constant value of one. In the SPSS Data Editor menu, go to Transform>Compute.Ģ. 'C:\Program Files\IBM\SPSS\Statistics\19\Samples\English\Employee data.sav'.) We will be calculating the 95% confidence interval for the variable SALARY.ġ. The English language version of Statistics 19, then by default this sample file would be in the path: (The sample data files are installed into the Samples directory where IBM Statistics was installed. Open the data set Employee data.sav, which comes with SPSS, then follow the steps outlined below. Here's an example to illustrate this method. Hence, you simply create a new variable with a constant value of 1 for use as the denominator and use the variable of interest as the numerator when selecting variables in the RATIO STATISTICS dialog box.
This work-around is based on the principle that the ratio of any number to 1 yields the original number. However, since the RATIO STATISTICS procedure provides this result only for ratios of two variables, you will need to employ a simple work-around to avail yourself of this functionality. The Ratio Statistics procedure (Analyze->Descriptive Statistics->Ratio) will print confidence intervals for medians in a pivot table.
To see Help pages for these methods, choose Topics in the Help menu of SPSS Statistics and enter the topic terms: median confidence interval. There are various methods to compute confidence intervals for medians in IBM SPSS Statistics.