Table of Contents
Mean absolute deviation (MAD) can be quickly and easily found using a TI-84 calculator. To use the calculator, the user must enter the data set into the calculator and select the “1-Var Stats” option from the STAT menu. Then the calculator will display the mean absolute deviation of the data set in the “MAD” field on the calculator’s display. With the TI-84 calculator, the user can quickly get an accurate measure of the MAD of a data set.
The mean absolute deviation is a way to measure the spread of values in a dataset.
It is calculated as:
Mean absolute deviation = (Σ |xi – x|) / n
- Σ: A fancy symbol that means “sum”
- xi: The ith data value
- x: The mean value
- n: The sample size
A low value for the mean absolute deviation tells us that the data values are concentrated close to each other while a high value tells us that the values are more spread out.
The following step-by-step example shows how to calculate the mean absolute deviation for the following dataset on a TI-84 calculator:
Dataset: 8,13,14,16,19,24
Step 1: Enter the Data
First, we will enter the data values.
Press Stat, then press EDIT. Then enter the values in column L1:
Step 2: Calculate the Absolute Deviations
Next, we will find the absolute deviation of each individual value from the mean.
To do so, highlight the top of column L2 and type in the following formula:
=abs(L1 - mean(L1))
Here’s how to actually type in this formula:
- Press 2nd, then press 0. Then press abs(. This will input abs( in the formula.
- Press 2nd, then press 1. Now you will have abs(L1 in the formula.
- Press the minus – button. Now you will have abs(L1- in the formula.
- Press 2nd, then press STAT. Scroll over to “MATH” and then press 3. Now you will have abs(L1-mean( in the formula.
- Press 2nd, then press 1. Now you will have abs(L1-mean(L1 in the formula.
- Press ) twice. Now you will have abs(L1-mean(L1)), which is the final formula.
Step 3: Calculate the Mean Absolute Deviation
Lastly, use the following steps to calculate the mean absolute deviation:
- Press 2nd and then press MODE to return to the home screen.
- Press 2nd and then press STAT. Scroll over to “MATH” and then press 3.
- Press 2nd and then press 2.
- Press the ) button.
Once you press Enter, the mean absolute deviation will be displayed:
The mean absolute deviation turns out to be 4.
This tells us that the average distance between the individual values and the mean value in this dataset is 4.