Advertisements
Advertisements
प्रश्न
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.
उत्तर
Here n1 = 15, n2 = 30, X1 = 45 Kg and X2 = 52 Kg.
∴ `bar"X"` = `("n"_1bar"X"_1 + "n"_2bar"X"_2)/("n"_1 + "n"_2) = (15 xx 45 + 30 xx 52)/(15 + 30)"Kg"`.
= `(2235)/(45)"kg"`
= 49·67kg.
Hence, the mean weight of the entire class is 49·67kg.
APPEARS IN
संबंधित प्रश्न
Calculate the mean for the following distribution:-
| x | 5 | 6 | 7 | 8 | 9 |
| f | 4 | 8 | 14 | 11 | 3 |
Find the mean of the following data:-
| x | 19 | 21 | 23 | 25 | 27 | 29 | 31 |
| f | 13 | 15 | 16 | 18 | 16 | 15 | 13 |
For the following distribution, calculate mean using all suitable methods:
| Size of item | 1 - 4 | 4 - 9 | 9 - 16 | 16 - 27 |
| Frequency | 6 | 12 | 26 | 20 |
Compute the mean for following data:
| Class | 1-3 | 3-5 | 5-7 | 7-9 |
| Frequency | 12 | 22 | 27 | 19 |
Find the mean of the following data, using direct method:
| Class | 0-100 | 100-200 | 200-300 | 300-400 | 400-500 |
| Frequency | 6 | 9 | 15 | 12 | 8 |
Find the mean of the following frequency distribution using step-deviation method
| Class | 0 – 10 | 10 – 20 | 20 – 30 | 30 – 40 | 40 – 50 |
| Frequency | 7 | 10 | 15 | 8 | 10 |
If the mean of observations x1, x2, x3, ....xn is `barx,` then the mean of new observations x1 + a, x2 + a, x3 + a, ........ xn + a is?
The daily income of a sample of 50 employees are tabulated as follows:
| Income (in Rs) |
1 – 200 | 201 – 400 | 401 – 600 | 601 – 800 |
| Number of employees |
14 | 15 | 14 | 7 |
Find the mean daily income of employees.
The weights (in kg) of 50 wrestlers are recorded in the following table:
| Weight (in kg) | 100 – 110 | 110 – 120 | 120 – 130 | 130 – 140 | 140 – 150 |
| Number of wrestlers |
4 | 14 | 21 | 8 | 3 |
Find the mean weight of the wrestlers.
Find the mean, median and mode of the given data:
| Class | 65 – 85 | 85 – 105 | 105 – 125 | 125 – 145 | 145 – 165 | 165 – 185 | 185 –205 |
| Frequency | 8 | 7 | 22 | 17 | 13 | 5 | 3 |
