Problem 103

Problem 103

Doug had scores of 80, 85, 75, and 80 on his first four exams in a course.

1. Find the mean, median, and mode for these exam scores.

2. Which “average” would Doug want the teacher to use in determining his grade?

3. What score would Doug have to get on a fifth exam-ination to raise his mean score to 84? Is ir reasonable to expect Dog to achieve that score?

Solution

1. mean = $\frac{80+85+75+80}{4}$ = $\frac{320}{4} = 80$

median= $\frac{80+80}{2} = 80$

moad = 80

2. In this situation all values are same but normally mean “average” Doug want the teacher to use in determining his grade

3. mean = $\frac{80+85+75+80+x}{5}$ = 84

320 + x = 84 $\ast$ 5

x = 420 – 320

x = 100

He needs 100 score in next exam to get the average of 100.

NO, because his last 4 scores average is 80 so not possible to get 100 in next exam.