Question

Question 9 Find the mean deviation about the mean for the data.




Income per day Number of persons

0-100 4

100-200 8

200-300 9

300-400 10

400-500 7

500-600 5

600-700 4

700-800 3

Class X1 - Maths -Statistics Page 361

Answer 1

see attachment,
we get ,
$\sum{f_i}=50\\\\\sum{f_id_i}=4\\\\\sum{f_i|x_i-\overline{x}|}=7896$
first of all we have to find Mean of given data,
$Mean(\overline{x})=A+\frac{\sum{f_id_i}}{\sum{f_i}}\times \: h\\\\=350+\frac{4}{50}\times \: 100\\\\=350+8=358$

now,
$Mean \: \: deviation \: \: about \: \: the \: \: mean = \frac{\sum{f_i|x_i-\overline{x}|}}{\sum{f_i}}\\\\=\frac{7896}{50}=157.92$

Answer 2

Answer:

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