The ages of students in a small primary school were recorded in the table below.
Age
5 - 6
7 - 8
9 -10
Frequency
29
40
38
Estimate the mean
A
7.7
B
7.5
C
7.8
D
7.6
Verified Correct Answer: A.
Step-by-Step Mathematical Solution
Class Interval
Class Mark
Frequency (f)
fx
5 - 6
5.5
29
5.5 x 29 = 159.5
7 - 8
7.5
40
7.5 x 40 = 300
9 - 10
9.5
38
9.5 x 38 = 361
\(\sum f = 107\)
\(\sum fx = 820.5\)
Mean = \(\frac{\sum fx}{\sum f} = \frac {820.5}{107}\) = 7.7 (1 d.p)
Source: WAEC / JAMB / NECO Classroom Archive (Record #67266)