Find the mean marks per student- using Step Deviation method method- - Marks 5 15 25 35 45 55- Number of students 12 18 27 20 17 6- -

Marks Frequency (fi) nbsp; Deviation (di) di nbsp;= (xi nbsp;– 25) nbsp; (fidi) 5 12 nbsp; 20 240 ...

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Standard X

Mathematics

Assumed Mean Method of Finding Mean

Find the mean...

Question

Find the mean marks per student, using Step Deviation method method:
$\begin{matrix} Marks & 5 & 15 & 25 & 35 & 45 & 55 Number of students & 12 & 18 & 27 & 20 & 17 & 6 \end{matrix}$

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Solution

Marks Frequency (f_i) Deviation (d_i)
d_i = (x_i – 25) (f_id_i)

5 12 -20 -240

15 18 -10 -180

25 = A 27 0 0

35 20 10 200

45 17 20 340

55 6 30 180

Total ∑fi=100 ∑(fi×di)=300

Let A = 25 be the assumed mean.

Then we have

$M e a n = A + \frac{\sum f_{i} d_{i}}{\sum f_{i}} = 25 + \frac{300}{100} = 28$

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Marks	Frequency (f_i)	Deviation (d_i) d_i = (x_i – 25)	(f_id_i)
5	12	-20	-240
15	18	-10	-180
25 = A	27	0	0
35	20	10	200
45	17	20	340
55	6	30	180
Total	∑fi=100		∑(fi×di)=300

Find the mean marks per student, using Step Deviation method method: Marks51525354555Number of students12182720176

Marks Frequency (fi) Deviation (di) di = (xi – 25) (fidi) 5 12 -20 -240 15 18 -10 -180 25 = A 27 0 0 35 20 10 200 45 17 20 340 55 6 30 180 Total ∑fi=100 ∑(fi×di)=300 Let A = 25 be the assumed mean. Then we have Mean=A+∑fidi∑fi=25+300100=28

Find the mean marks per student, using Step Deviation method method:
$\begin{matrix} Marks & 5 & 15 & 25 & 35 & 45 & 55 Number of students & 12 & 18 & 27 & 20 & 17 & 6 \end{matrix}$