JAMB - Mathematics (2011 - No. 33)
\(\begin{array}{c|c} Class Intervals & 0 - 2 & 3 - 5 & 6 - 8 & 9 - 11 & \\ \hline Frequency & 3 & 2 & 5 & 3 &\end{array}\)
Find the mode of the above distribution.
Find the mode of the above distribution.
9
8
10
7
Explanation
Mode = L1 + (\(\frac{D_1}{D_1 + D_2}\))C
D1 = frequency of modal class - frequency of the class before it
D1 = 5 - 2 = 3
D2 = frequency of modal class - frequency of the class that offers it
D2 = 5 - 3 = 2
L1 = lower class boundary of the modal class
L1 = 5 - 5
C is the class width = 8 - 5.5 = 3
Mode = L1 + (\(\frac{D_1}{D_1 + D_2}\))C
= 5.5 + \(\frac{3}{2 + 3}\)C
= 5.5 + \(\frac{3}{5}\) x 3
= 5.5 + \(\frac{9}{5}\)
= 5.5 + 1.8
= 7.3 \(\approx\) = 7
D1 = frequency of modal class - frequency of the class before it
D1 = 5 - 2 = 3
D2 = frequency of modal class - frequency of the class that offers it
D2 = 5 - 3 = 2
L1 = lower class boundary of the modal class
L1 = 5 - 5
C is the class width = 8 - 5.5 = 3
Mode = L1 + (\(\frac{D_1}{D_1 + D_2}\))C
= 5.5 + \(\frac{3}{2 + 3}\)C
= 5.5 + \(\frac{3}{5}\) x 3
= 5.5 + \(\frac{9}{5}\)
= 5.5 + 1.8
= 7.3 \(\approx\) = 7
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