Answer:
Range.
Step-by-step explanation:
Alan must use the measure called Range, which indicates the dispersion between the extreme values of a variable. It is calculated as the difference between the highest and the lowest value of the variable. It is denoted as R. First the data is sorted, then it is calculated as:
R = x (n) - x (1) where,
x (n): It is the largest value of the variable.
x (1): It is the smallest value of the variable.
In the given case (5, 6, 7, 5, 7, 9, 2, 4, 8, and 7), we sort the data, and get,
2, 4, 5, 5, 6, 7, 7, 7, 8, 9
x (n) = 9
X (1) = 2
R = 9 - 2 = 7
Hope this helps!