Question

b) Calculate the mean of the following distribution by short cut method upto one
decimal place.
| Marks T. 10-20
20-30
30-40
140,50
50-60
60-70
AstPaperz.com
70-80
80-90 90-100
20
Number
or
Student
2
4
5
16
20
10
6
8
4


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Answer 1

Given .

✨Distribution table ...

✨use shortcut method

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✨Concept to find out -

Find mean by shortcut method by one decimal place.

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✨Formula used ....

$mean = \\ \boxed{a + \frac{sum \: of \: fd}{total \: no \: of \: student} }$

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Solution...

Refer above attachment table ....

Fill the values in formula.

$55 + \frac{160}{75} \\ \\ = > 55 + 2.133 \\ \\ = > > 57.13$

$\color{red} \boxed{mean = > 57.13}$

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So the

MEAN => 57.133.

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THANKS

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SOME OTHER FORMULAS REALTED TO THIS .

✨In direct method

$\color{orange} \boxed{mean = > \frac{sum \: of \: fm}{total \: no. \: of \: f \: } }$

✨In step deviation method .

$\color{hotpink} \boxed{mean = > a + \frac{sum \: total \: of \: fu}{total \: of \: f} \times h}$

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