Lucia has been recording her grades on her Spanish quizzes. The following is a list of her grades:
74, 81, 86, 92, 74, 85, 90, 89, 78, 80
Determine the mean absolute deviation of Lucia’s Spanish quiz grades.
(1 point)
Responses
55
55
5.5
5.5
82.9
82.9
8.29
To find the mean absolute deviation, first calculate the mean of Lucia's grades:
(74 + 81 + 86 + 92 + 74 + 85 + 90 + 89 + 78 + 80) / 10 = 829 / 10 = 82.9
Next, find the absolute deviation of each grade from the mean:
|74 - 82.9| = 8.9
|81 - 82.9| = 1.9
|86 - 82.9| = 3.1
|92 - 82.9| = 9.1
|74 - 82.9| = 8.9
|85 - 82.9| = 2.1
|90 - 82.9| = 7.1
|89 - 82.9| = 6.1
|78 - 82.9| = 4.9
|80 - 82.9| = 2.9
Add up all the absolute deviations and divide by the number of grades (10) to find the mean absolute deviation:
(8.9 + 1.9 + 3.1 + 9.1 + 8.9 + 2.1 + 7.1 + 6.1 + 4.9 + 2.9) / 10 = 55 / 10 = 5.5
Therefore, the mean absolute deviation of Lucia's Spanish quiz grades is 5.5.