Question

consider the following test scores obtained by a class.
test score | 90 | 80 | 70 | 60 | 50
frequency | 1 | 3 | 12 | 6 | 2
find the range and mean (rounded to the nearest unit).
range
mean

Explanation:

Step1: Calculate the range

The range is the difference between the maximum and minimum values. Here, the maximum test score is 90 and the minimum is 50. So, range = 90 - 50 = 40.

Step2: Calculate the mean

First, find the sum of (test score × frequency) for all scores.
For 90: \(90\times1 = 90\)
For 80: \(80\times3 = 240\)
For 70: \(70\times12 = 840\)
For 60: \(60\times6 = 360\)
For 50: \(50\times2 = 100\)
Now, sum these products: \(90 + 240 + 840 + 360 + 100 = 1630\)
Next, find the total number of students (sum of frequencies): \(1 + 3 + 12 + 6 + 2 = 24\)
Mean = \(\frac{1630}{24}\approx 68\) (rounded to the nearest unit)

Answer:

range: 40
mean: 68