JAMB - Mathematics (2023 - No. 17)

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

7.7
7.5
7.8
7.6

Explanation

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)

 

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