Answer with explanation:
Test Scores of Shania's in 8 subject are: 88, 91, 85, 74, 69, 72, 80, and 87.
To calculate mean we add all the variate and divide by total number of Variate in the data set.
So, Mean of the Data set
To calculate , how much the scores on her tests vary, on average, from the mean score
We will Calculate mean absolute Deviation.
To calculate it,we will find absolute difference of each variate from mean.
| 88 - 80.75|=7.25
|91-80.75|=10.25
|85 -80.75|=4.25
|74-80.75|=6.75
......
........
Then Shania should calculate mean of the new data set obtained,which is absolute difference of each variate from mean.
→The Measure that,Shania should use to find how much the scores on her tests vary, on average, from the mean score is:
Mean absolute deviation