1. Calculate Mean deviation from the following grouped data
Solution:
Mean deviation :
`x` `(1)` | `f` `(2)` | `f*x` `(3)=(2)xx(1)` | `|x-bar x|=|x-2.2|` `(4)` | `f*|x-bar x|` `(5)=(2)xx(4)` |
0 | 1 | 0 | 2.2 | 2.2 |
1 | 5 | 5 | 1.2 | 6 |
2 | 10 | 20 | 0.2 | 2 |
3 | 6 | 18 | 0.8 | 4.8 |
4 | 3 | 12 | 1.8 | 5.4 |
--- | --- | --- | --- | --- |
-- | `n=25` | `sum f*x=55` | -- | `sum f*|x-bar x|=20.4` |
Mean `bar x=(sum f x)/n`
`=55/25`
`=2.2`
Mean deviation of Mean
`delta bar x = (sum f*|x - bar x|)/n`
`delta bar x = 20.4/25`
`delta bar x = 0.816`
Coefficient of Mean deviation `=(delta bar x)/(bar x)`
`=0.816/2.2`
`=0.3709`
2. Calculate Mean deviation from the following grouped data
X | Frequency |
10 | 3 |
11 | 12 |
12 | 18 |
13 | 12 |
14 | 3 |
Solution:
Mean deviation :
`x` `(1)` | `f` `(2)` | `f*x` `(3)=(2)xx(1)` | `|x-bar x|=|x-12|` `(4)` | `f*|x-bar x|` `(5)=(2)xx(4)` |
10 | 3 | 30 | 2 | 6 |
11 | 12 | 132 | 1 | 12 |
12 | 18 | 216 | 0 | 0 |
13 | 12 | 156 | 1 | 12 |
14 | 3 | 42 | 2 | 6 |
--- | --- | --- | --- | --- |
-- | `n=48` | `sum f*x=576` | -- | `sum f*|x-bar x|=36` |
Mean `bar x=(sum f x)/n`
`=576/48`
`=12`
Mean deviation of Mean
`delta bar x = (sum f*|x - bar x|)/n`
`delta bar x = 36/48`
`delta bar x = 0.75`
Coefficient of Mean deviation `=(delta bar x)/(bar x)`
`=0.75/12`
`=0.0625`
3. Calculate Mean deviation from the following grouped data
Class | Frequency |
2 - 4 | 3 |
4 - 6 | 4 |
6 - 8 | 2 |
8 - 10 | 1 |
Solution:
Mean deviation :
Mean `bar x=(sum f x)/(sum f)`
`=52/10`
`=5.2`
Class `(1)` | `f` `(2)` | Mid value (`x`) `(3)` | `f*x` `(4)=(2)xx(3)` | `|x-bar x|=|x-5.2|` `(5)` | `f*|x-bar x|` `(6)=(2)xx(5)` |
2 - 4 | 3 | 3 | 9 | 2.2 | 6.6 |
4 - 6 | 4 | 5 | 20 | 0.2 | 0.8 |
6 - 8 | 2 | 7 | 14 | 1.8 | 3.6 |
8 - 10 | 1 | 9 | 9 | 3.8 | 3.8 |
--- | --- | --- | --- | --- | --- |
-- | `n=10` | -- | `sum f*x=52` | -- | `sum f*|x-bar x|=14.8` |
Mean deviation of Mean
`delta bar x = (sum f*|x - bar x|)/n`
`delta bar x = 14.8/10`
`delta bar x = 1.48`
Coefficient of Mean deviation `=(delta bar x)/(bar x)`
`=1.48/5.2`
`=0.2846`
4. Calculate Mean deviation from the following grouped data
Class | Frequency |
0 - 2 | 5 |
2 - 4 | 16 |
4 - 6 | 13 |
6 - 8 | 7 |
8 - 10 | 5 |
10 - 12 | 4 |
Solution:
Mean deviation :
Mean `bar x=(sum f x)/(sum f)`
`=256/50`
`=5.12`
Class `(1)` | `f` `(2)` | Mid value (`x`) `(3)` | `f*x` `(4)=(2)xx(3)` | `|x-bar x|=|x-5.12|` `(5)` | `f*|x-bar x|` `(6)=(2)xx(5)` |
0 - 2 | 5 | 1 | 5 | 4.12 | 20.6 |
2 - 4 | 16 | 3 | 48 | 2.12 | 33.92 |
4 - 6 | 13 | 5 | 65 | 0.12 | 1.56 |
6 - 8 | 7 | 7 | 49 | 1.88 | 13.16 |
8 - 10 | 5 | 9 | 45 | 3.88 | 19.4 |
10 - 12 | 4 | 11 | 44 | 5.88 | 23.52 |
--- | --- | --- | --- | --- | --- |
-- | `n=50` | -- | `sum f*x=256` | -- | `sum f*|x-bar x|=112.16` |
Mean deviation of Mean
`delta bar x = (sum f*|x - bar x|)/n`
`delta bar x = 112.16/50`
`delta bar x = 2.2432`
Coefficient of Mean deviation `=(delta bar x)/(bar x)`
`=2.2432/5.12`
`=0.4381`
This material is intended as a summary. Use your textbook for detail explanation.
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