Question

Help please on this math problem: The prices of backpacks at a store are 22, 16, 39, 35, 19, 34, 20, and 26. Find the Mean Absolute Deviation (MAD) of the prices.
*i just don’t know if I should round the price to divide, since the answer for the mean ends up being a decimal.*

Answer 1

Answer: 7.22
(note: this is a result after rounding. The result before rounding was 7.21875)

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Explanation:

Given Set of Values = {22, 16, 39, 35, 19, 34, 20, 26}

Add up the values: 22+16+39+35+19+34+20+26 = 211
Divide that sum by 8 as there are 8 values: 211/8 = 26.375

The mean is 26.375

Now subtract the mean from each data value. Apply the absolute value to ensure the difference is never negative

|22 - 26.375| = 4.375
|16 - 26.375| = 10.375
|39 - 26.375| = 12.625
|35 - 26.375| = 8.625
|19 - 26.375| = 7.375
|34 - 26.375| = 7.625
|20 - 26.375| = 6.375
|26 - 26.375| = 0.375

Add up those results
4.375+10.375+12.625+8.625+7.375+7.625+6.375+0.375 = 57.75
Then divide by 8 
57.75/8 = 7.21875

The mean absolute deviation of the prices is 7.21875
Rounded to two decimal places, it is 7.22
Since we're talking about money, it makes sense to round to the nearest penny.