Comprehensive Calculator Guide
This calculator finds the mean absolute deviation, the average unsigned distance of values from their mean, a simple measure of spread taught before the standard deviation. For 4, 7, 9, 10, 15 the mean is 9 and the MAD 2.8, with each distance shown.
MAD
Mean, unsigned distances, their sum, divided by n. The SD squares distances, so it is never below the MAD; the MAD is easier to explain.
How to Use
- Enter the data.
- No need for the mean first.
- Press “Calculate” to see the MAD and each distance.
Formula Used
MAD = Σ|x − x̄| ÷ n
Practical Examples
- Example 1
- 4 to 15: 2.8.
- Example 2
- Marks: about 8.59.
Important Tips
- Make every distance positive.
- Signed deviations sum to zero.
- Use it to introduce spread.
Common Mistakes to Avoid
- Adding signed deviations.
- Confusing it with the median absolute deviation.
- Dividing by n − 1.
Frequently Asked Questions
- What is it?
- The mean unsigned distance from the mean.
- Why absolute values?
- Signed deviations cancel.
- Bigger than the SD?
- No.