Advertisements
Advertisements
प्रश्न
Find the mean of the following frequency distribution, using the assumed-mean method:
| Class | 100 – 120 | 120 – 140 | 140 – 160 | 160 – 180 | 180 – 200 |
| Frequency | 10 | 20 | 30 | 15 | 5 |
उत्तर
| Class | Frequency `(f_i)` | Mid values `(x_i)` | Deviation `(d_i) d_i = (x_i – 150)` |
`(f_i × d_i)` |
| 100 – 120 | 10 | 110 | -40 | -400 |
| 120 – 140 | 20 | 130 | -20 | -400 |
| 140 – 160 | 30 | 150 = A | 0 | 0 |
| 160 – 180 | 15 | 170 | 20 | 300 |
| 180 – 200 | 5 | 190 | 40 | 200 |
| `Ʃ f_i` = 80 | `Ʃ (f_i × d_i)` = -300 |
Let A = 150 be the assumed mean. Then we have:
Mean, x = ` A + (Ʃ (f_i × d_i))/(Ʃ f_i)`
=150 + `(-300)/80`
`=(1200-30)/8`
=`1170/8 = 146.24`
∴ = x = 146 .24
APPEARS IN
संबंधित प्रश्न
The following distribution shows the daily pocket allowance of children of a locality. The mean pocket allowance is Rs.18. Find the missing frequency f.
| Daily pocket allowance (in Rs | 11 - 13 | 13 - 15 | 15 - 17 | 17 - 19 | 19 - 21 | 21 - 23 | 23 - 25 |
| Number of workers | 7 | 6 | 9 | 13 | f | 5 | 4 |
The table below shows the daily expenditure on food of 25 households in a locality.
| Daily expenditure (in Rs) | 100 − 150 | 150 − 200 | 200 − 250 | 250 − 300 | 300 − 350 |
| Number of households | 4 | 5 | 12 | 2 | 2 |
Find the mean daily expenditure on food by a suitable method.
Find the mean of the following data, using direct method:
| Class | 25-35 | 35-45 | 45-55 | 55-65 | 65-75 |
| Frequency | 6 | 10 | 8 | 12 | 4 |
Mean of a certain number of observation is `overlineX`. If each observation is divided by m(m ≠ 0) and increased by n, then the mean of new observation is
There are 45 students in a class, in which 15 are girls. The average weight of 15 girls is 45 kg and 30 boys is 52 kg. Find the mean weight in kg of the entire class.
Find the mean wage of a worker from the following data:
| Wages (In ₹) | 1400 | 1450 | 1500 | 1550 | 1600 | 1650 | 1700 |
| Number of workers | 15 | 20 | 18 | 27 | 15 | 3 | 2 |
The average weight of a group of 25 men was calculated to be 78.4 kg. It was discovered later that one weight was wrongly entered as 69 kg instead of 96 kg. What is the correct average?
In the formula `barx = a + h((sumf_iu_i)/(sumf_i))`, for finding the mean of grouped frequency distribution, ui = ______.
The following table gives the number of pages written by Sarika for completing her own book for 30 days:
| Number of pages written per day |
16 – 18 | 19 – 21 | 22 – 24 | 25 – 27 | 28 – 30 |
| Number of days | 1 | 3 | 4 | 9 | 13 |
Find the mean number of pages written per day.
The mean of 6 distinct observations is 6.5 and their variance is 10.25. If 4 out of 6 observations are 2, 4, 5 and 7, then the remaining two observations are ______.
