find the mean of the following data by shortcut method - Maths - Statistics

Question

find the mean of the following data by shortcut method

marks
20
22
25
30
35
39
45
50
total

frequency
4
6
8
10
8
7
5
2
50

tell me the answer fast i have m xam on monday !!

Santosh Kumar · Accepted Answer

Marks xi Assumed mean (A) $Deviation d_{i} = x_{i} - \bar{x}$ Frequency f fdi 20 20 â€“ 35 = â€“ 15 4 (â€“ 15) (4) = â€“ 60 22 22 â€“ 35 = â€“ 13 6 (â€“ 13) (6) = â€“ 78 25 25 â€“ 35 = â€“ 10 8 (â€“ 10) (8) = â€“ 80 30 30 â€“ 35 = â€“ 5 10 (â€“ 5) (10) = â€“ 50 35 35 35 â€“ 35 = 0 8 0 (8) = 0 39 39 â€“ 35 = 4 7 4 (7) = 28 45 45 â€“ 35 = 10 5 10 (5) = 50 50 50 â€“ 35 = 15 2 15 (2) = 30 $Mean = A + (\frac{Σ_{i = 1}^{n} f i d i}{Σ_{i = 1}^{n} f i})$ $= 35 + \frac{- 60 - 78 - 80 - 50 + 0 + 28 + 50 + 30}{50} = \frac{35 - 160}{50} = \frac{35 - 16}{5} = \frac{175 - 16}{5} = \frac{159}{5} = 31 8$

Marks x_i	Assumed mean (A)	$Deviation d_{i} = x_{i} - \bar{x}$	Frequency f	fd_i
20		20 – 35 = – 15	4	(– 15) (4) = – 60
22		22 – 35 = – 13	6	(– 13) (6) = – 78
25		25 – 35 = – 10	8	(– 10) (8) = – 80
30		30 – 35 = – 5	10	(– 5) (10) = – 50
35	35	35 – 35 = 0	8	0 (8) = 0
39		39 – 35 = 4	7	4 (7) = 28
45		45 – 35 = 10	5	10 (5) = 50
50		50 – 35 = 15	2	15 (2) = 30

find the mean of the following data by shortcut method marks 20 22 25 30 35 39 45 50 total frequency 4 6 8 10 8 7 5 2 50 tell me the answer fast i have m xam on monday..........!!

find the mean of the following data by shortcut method

marks 20 22 25 30 35 39 45 50 total

frequency 4 6 8 10 8 7 5 2 50

tell me the answer fast i have m xam on monday..........!!