Question

Question 6 Find the mean deviation about the mean for the data.

xi 10 30 50 70 90

fi 4 24 28 16 8

Class X1 - Maths -Statistics Page 360

Answer 1

process :
first of all we have to find out mean of given observations .
for mean use the formula,
$\overline{x}= \frac{\sum{f_ix_i}}{\sum{f_i}}$
and then calculate Mean deviation about mean
by using formula,
$MD=\frac{\sum{f_i|x_i-\overline{x}|}}{\sum{f_i}}$

see attachment , here,
$\sum{f_i}=80\\\\\sum{f_ix_i}=4000\\\\\sum{f_i|x_i-\overline{x}|}=1280$
now,
$Mean(\overline{x})=\frac{\sum{f_ix_i}}{\sum{f_i}}\\\\=\frac{4000}{80}\\\\=50$
finally finding Mean deviation ,
$MEAN\: deviation\: about\:mean=\frac{\sum{f_i|x_i-\overline{x}|}}{\sum{f_i}} \\ \\ = \frac{1280}{80} \\ \\ = 16$

Answer 2

Step-by-step explanation:

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