Score
0 - 4
5 - 9
10 - 14
Frequency
2
1
2
The table shows the distribution of the scores of some students in a test. Calculate the mean scores.
A
5.6
B
6.2
C
6.6
D
7.0
Verified Correct Answer: D.
Step-by-Step Mathematical Solution
To calculate the mean of grouped data,
- First step to determine the midpoint (x) of each interval or class.
0 - 4 ►2
5 - 9 ► 7
10 - 14 ►12
These midpoints must then be multiplied by the frequencies of the corresponding classes:
2 X 2 = 4
1 X 7 = 7
2 X 12 = 24
Mean = ( 24 + 7 + 4) \div ( 2 + 1 + 2 )
: Mean = 7
Source: Myschool Past Questions Archive (Record #45822)