Find the mean of the following frequency table by step-deviation method- -3 MARKS- ibegin array -c- c - Whe Class interval - Frequency Whline10-15 - 5 Whline15-20 - 6 Whline 20-25 - 8 Whline 25-30 - 12 Whline30-35 - 6 Whline35-40 - 3 Whline

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Standard X

Mathematics

Mode for Grouped Data

Find the mean...

Question

Find the mean of the following frequency table by step-deviation method: [3 MARKS]
$\begin{matrix} C l a s s i n t e r v a l & F r e q u e n c y 10 - 15 & 5 15 - 20 & 6 20 - 25 & 8 25 - 30 & 12 30 - 35 & 6 35 - 40 & 3 \end{matrix}$

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Solution

Formula: 1 Mark
Solution: 2 Marks

Here, choosing A = 27.5 and i = 5, we may arrange the data as given below:
$\begin{matrix} C l a s s & M i d v a l u e & F r e q u e n c y & u = \frac{x - A}{i} & f u i n t e r v a l & (x) 10 - 15 & 12.5 & 5 & - 3 & - 15 15 - 20 & 17.5 & 6 & - 2^{-} 12 20 - 25 & 22.5 & 8 & - 1 & - 8 25 - 30 & 27.5 = A & 12 & 0 & 0 30 - 35 & 32.5 & 6 & 1 & 6 35 - 40 & 37.5 & 3 & 2 & 6 T o t a l & \sum f = 40 & \sum f u = - 23 \end{matrix}$
$∴$ Mean $= A + (\frac{\sum f u}{\sum f}) \times i = 27.5 + (\frac{- 23}{40}) \times 5$
= 27.5 - 2.88 = 24.62

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Find the mean of the following frequency table by step-deviation method: [3 MARKS] Class intervalFrequency10−15515−20620−25825−301230−35635−403

Find the mean of the following frequency table by step-deviation method: [3 MARKS]
$\begin{matrix} C l a s s i n t e r v a l & F r e q u e n c y 10 - 15 & 5 15 - 20 & 6 20 - 25 & 8 25 - 30 & 12 30 - 35 & 6 35 - 40 & 3 \end{matrix}$