Guide SPSS how to: Measures of Central Tendency and Measures of Dispersion

Here’s a guide for 1st year students to calculate measures of central tendency and dispersion in SPSS:

Calculating Measures of Central Tendency

1. Open your dataset in SPSS.
2. Click on “Analyze” in the top menu, then select “Descriptive Statistics” > “Frequencies”
3. In the new window, move the variables you want to analyze into the “Variable(s)” box
4. Click on the “Statistics” button
5. In the “Frequencies: Statistics” window, check the boxes for:

• Mean
• Median
• Mode

1. Click “Continue” and then “OK” to run the analysis

Calculating Measures of Dispersion

1. Follow steps 1-4 from above.
2. In the “Frequencies: Statistics” window, also check the boxes for:

• Standard deviation
• Range
• Minimum
• Maximum

1. For interquartile range, check the box for “Quartiles”
2. Click “Continue” and then “OK” to run the analysis.

Interpreting the Results

• Mean: The average of all values
• Median: The middle value when data is ordered
• Mode: The most frequently occurring value
• Range: The difference between the highest and lowest values
• Standard Deviation: Measures the spread of data from the mean
• Interquartile Range: The range of the middle 50% of the data.

Choosing the Appropriate Measure

• For nominal data: Use mode only.
• For ordinal data: Use median and mode.
• For interval/ratio data: Use mean, median, and mode.

Remember, if your distribution is skewed, the median may be more appropriate than the mean for interval/ratio data.