Big Ideas Math: Modeling Real Life, Grade 6
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Exercise 22 Page 449

The mean absolute deviation is the average of the absolute values of the differences between the mean and each value in the data set. Start by calculating the mean of the given set of numbers.

Mean Absolute Deviation: 26
Interpretation: The prices of tablets, on average, are 26 dollars away from the mean 154.

Practice makes perfect

The mean absolute deviation (MAD) is the average of the absolute values of the differences between the mean and each value in the data set. Let's see the given data set.

Prices of Tablets (dollars)
130 150 190 100 175
120 165 140 180 190

We will start by calculating the mean of the given set of numbers. We can see that there are 10 values in our data set. Let's calculate the mean!

Mean = Sum of values/Number of values
Mean = 130+150+190+100+175+120+165+140+180+190/10
Mean = 1540/10
Mean = 154

We found that the mean of the given data set is 154. We are ready to calculate the MAD. We noted before that the MAD of a set of data is the average of the absolute values of the differences between the mean and each value in the data set. | x- x_1|+| x- x_2|+...+| x- x_n|/n In this formula, x_1,...,x_n are the values in the set of data, x is the mean, and n is the number of values. We already know that x= 154 and n= 10. Let's use a table to find the sum of the absolute values of the differences.

x_i x-x_i |x-x_i|
130 154- 130=24 |24|=24
150 154- 150=4 |4|=4
190 154- 190=-36 |-36|=36
100 154- 100=54 |54|=54
175 154- 175=- 21 |- 21|=21
120 154- 120=34 |34|=34
165 154- 165=-11 |-11|=11
140 154- 140=14 |14|=14
180 154- 180=-26 |-26|=26
190 154- 190=- 36 |- 36|=36
Sum of Values 260

Finally, we need to divide by 10. This will give us the average. Mean Absolute Deviation (MAD) 260/10=26 A MAD of 26 indicates that the data, on average, are 26 units away from the mean. In the context of the problem, this means that the prices of tablets, on average, are 26 dollars away from the mean 154.