1. Calculate Quintile-2 from the following grouped data
Solution:
`x` | Frequency `f` | `cf` |
0 | 1 | 1 |
1 | 5 | 6 |
2 | 10 | 16 |
3 | 6 | 22 |
4 | 3 | 25 |
--- | --- | --- |
| `n = 25` | -- |
Here, `n = 25`
`"Quintile"_2 = ((2(n+1))/5)^(th)` value of the observation
`=((2*26)/5)^(th)` value of the observation
`=(10.4)^(th)` value of the observation
`=2`
2. Calculate Quintile-2 from the following grouped data
X | Frequency |
10 | 3 |
11 | 12 |
12 | 18 |
13 | 12 |
14 | 3 |
Solution:
`x` | Frequency `f` | `cf` |
10 | 3 | 3 |
11 | 12 | 15 |
12 | 18 | 33 |
13 | 12 | 45 |
14 | 3 | 48 |
--- | --- | --- |
| `n = 48` | -- |
Here, `n = 48`
`"Quintile"_2 = ((2(n+1))/5)^(th)` value of the observation
`=((2*49)/5)^(th)` value of the observation
`=(19.6)^(th)` value of the observation
`=12`
3. Calculate Quintile-4 from the following grouped data
Class | Frequency |
2 - 4 | 3 |
4 - 6 | 4 |
6 - 8 | 2 |
8 - 10 | 1 |
Solution:
Class | Frequency `f` | `cf` |
2 - 4 | 3 | 3 |
4 - 6 | 4 | 7 |
6 - 8 | 2 | 9 |
8 - 10 | 1 | 10 |
--- | --- | --- |
| `n = 10` | -- |
Here, `n = 10`
`"Quintile"_4` class :
Class with `((4n)/5)^(th)` value of the observation in `cf` column
`=((4*10)/5)^(th)` value of the observation in `cf` column
`=(8)^(th)` value of the observation in `cf` column
and it lies in the class `6 - 8`.
`:. "Quintile"_4` class : `6 - 8`
The lower boundary point of `6-8` is `6`.
`:. L=6`
`"Quintile"_4=L+((4 n)/5 - cf)/f * c`
`=6+(8-7)/2*2`
`=6+(1)/2*2`
`=6+1`
`=7`
4. Calculate Quintile-3 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:
Class | Frequency `f` | `cf` |
0 - 2 | 5 | 5 |
2 - 4 | 16 | 21 |
4 - 6 | 13 | 34 |
6 - 8 | 7 | 41 |
8 - 10 | 5 | 46 |
10 - 12 | 4 | 50 |
--- | --- | --- |
| `n = 50` | -- |
Here, `n = 50`
`"Quintile"_3` class :
Class with `((3n)/5)^(th)` value of the observation in `cf` column
`=((3*50)/5)^(th)` value of the observation in `cf` column
`=(30)^(th)` value of the observation in `cf` column
and it lies in the class `4 - 6`.
`:. "Quintile"_3` class : `4 - 6`
The lower boundary point of `4-6` is `4`.
`:. L=4`
`"Quintile"_3=L+((3 n)/5 - cf)/f * c`
`=4+(30-21)/13*2`
`=4+(9)/13*2`
`=4+1.3846`
`=5.3846`
5. Calculate Quintile-3 from the following grouped data
Class | Frequency |
10 - 20 | 15 |
20 - 30 | 25 |
30 - 40 | 20 |
40 - 50 | 12 |
50 - 60 | 8 |
60 - 70 | 5 |
70 - 80 | 3 |
Solution:
Class | Frequency `f` | `cf` |
10 - 20 | 15 | 15 |
20 - 30 | 25 | 40 |
30 - 40 | 20 | 60 |
40 - 50 | 12 | 72 |
50 - 60 | 8 | 80 |
60 - 70 | 5 | 85 |
70 - 80 | 3 | 88 |
--- | --- | --- |
| `n = 88` | -- |
Here, `n = 88`
`"Quintile"_3` class :
Class with `((3n)/5)^(th)` value of the observation in `cf` column
`=((3*88)/5)^(th)` value of the observation in `cf` column
`=(52.8)^(th)` value of the observation in `cf` column
and it lies in the class `30 - 40`.
`:. "Quintile"_3` class : `30 - 40`
The lower boundary point of `30-40` is `30`.
`:. L=30`
`"Quintile"_3=L+((3 n)/5 - cf)/f * c`
`=30+(52.8-40)/20*10`
`=30+(12.8)/20*10`
`=30+6.4`
`=36.4`
6. Calculate Quintile-1 from the following grouped data
Class | Frequency |
20 - 25 | 110 |
25 - 30 | 170 |
30 - 35 | 80 |
35 - 40 | 45 |
40 - 45 | 40 |
45 - 50 | 35 |
Solution:
Class | Frequency `f` | `cf` |
20 - 25 | 110 | 110 |
25 - 30 | 170 | 280 |
30 - 35 | 80 | 360 |
35 - 40 | 45 | 405 |
40 - 45 | 40 | 445 |
45 - 50 | 35 | 480 |
--- | --- | --- |
| `n = 480` | -- |
Here, `n = 480`
`"Quintile"_1` class :
Class with `(n/5)^(th)` value of the observation in `cf` column
`=(480/5)^(th)` value of the observation in `cf` column
`=(96)^(th)` value of the observation in `cf` column
and it lies in the class `20 - 25`.
`:. "Quintile"_1` class : `20 - 25`
The lower boundary point of `20-25` is `20`.
`:. L=20`
`"Quintile"_1=L+(( n)/5 - cf)/f * c`
`=20+(96-0)/110*5`
`=20+(96)/110*5`
`=20+4.3636`
`=24.3636`
This material is intended as a summary. Use your textbook for detail explanation.
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