To find the mean, you add up all the numbers and divide by the total count:
55 + 60 + 70 + 70 + 75 + 75 + 75 + 80 + 80 + 85 + 85 + 85 + 85 + 90 + 90 + 95 + 100 = 1430
There are 17 numbers in total, so the mean is 1430/17 = 84.12 (rounded to two decimal places).
To find the MAD (Mean Absolute Deviation), you first find the absolute difference between each number and the mean, then calculate the average of these differences. Here are the absolute differences:
|55 - 84.12| = 29.12
|60 - 84.12| = 24.12
|70 - 84.12| = 14.12
|70 - 84.12| = 14.12
|75 - 84.12| = 9.12
|75 - 84.12| = 9.12
|75 - 84.12| = 9.12
|80 - 84.12| = 4.12
|80 - 84.12| = 4.12
|85 - 84.12| = 0.88
|85 - 84.12| = 0.88
|85 - 84.12| = 0.88
|85 - 84.12| = 0.88
|90 - 84.12| = 5.88
|90 - 84.12| = 5.88
|95 - 84.12| = 10.88
|100 - 84.12| = 15.88
Adding up these absolute differences gives us:
29.12 + 24.12 + 14.12 + 14.12 + 9.12 + 9.12 + 9.12 + 4.12 + 4.12 + 0.88 + 0.88 + 0.88 + 0.88 + 5.88 + 5.88 + 10.88 + 15.88 = 140.72
To find the MAD, divide this sum by the total count (17):
140.72/17 ā 8.28 (rounded to two decimal places)
Therefore, the Mean Absolute Deviation is approximately 8.28.