68
Find mean and mode of the following frequency distribution :
Class: 10-30 30-50 50-70 70-90 90-110 110-130 130-150
Frequency: 6 8 12 10 14 11 9
Class: 10-30 30-50 50-70 70-90 90-110 110-130 130-150
Frequency: 6 8 12 10 14 11 9
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Correct table (I) (2 Marks)
$\therefore$ Mean = $\bar{x} = \frac{5940}{70}$ (II) (1/2 Mark)
$= 84.8$ (approx.) (III) (1/2 Mark)
Modal Class = $90 - 110$ (IV) (1/2 Mark)
$\therefore$ Mode = $90 + \frac{14-10}{28-10-11} \times 20$ (V) (1 Mark)
$= 101.4$ (approx.) (VI) (1/2 Mark)
$\therefore$ Mean = $\bar{x} = \frac{5940}{70}$ (II) (1/2 Mark)
$= 84.8$ (approx.) (III) (1/2 Mark)
Modal Class = $90 - 110$ (IV) (1/2 Mark)
$\therefore$ Mode = $90 + \frac{14-10}{28-10-11} \times 20$ (V) (1 Mark)
$= 101.4$ (approx.) (VI) (1/2 Mark)