Question

The grade of student on six examinations were 84, 91, 72, 68, 87, and 78. What is the arithmetic mean of the grades?

a. 88
b. 60
c. 70
d. 80

Answer 1

The grades of student on six examinations were 84, 91, 72, 68, 87, and 78. What is the arithmetic mean of the grades? a. 88 b. 60 c. 70 d. 80

Solution

The grades were 84 91 72 68 87 78 [Original data set].

The average of the data values in a data set is called mean.

$$\text{Arithmetic mean} = \frac{\text{Sum of data values}}{\text{Number of data values}}.$$

The arithmetic mean of the grades is

$$\frac{84 + 91 + 72 + 68 + 87 + 78}{6} = 80.$$

Answer: d. 80.