Advertisements
Advertisements
प्रश्न
The following table gives the number of boys of a particular age in a class of 40 students. Calculate the mean age of the students
| Age (in years) | 15 | 16 | 17 | 18 | 19 | 20 |
| No. of students | 3 | 8 | 10 | 10 | 5 | 4 |
उत्तर
| x | f | fx |
| 15 | 3 | 45 |
| 16 | 8 | 128 |
| 17 | 10 | 170 |
| 18 | 10 | 180 |
| 19 | 5 | 95 |
| 20 | 4 | 80 |
| `sum`f = N = 40 | `sum`fx = 698 |
Mean age `=(sumfx)/N`
`=698/40=17.45` years
∴ Mean age = 17.45 years
APPEARS IN
संबंधित प्रश्न
The following table gives the literacy rate (in percentage) of 35 cities. Find the mean literacy rate.
| Literacy rate (in %) | 45 − 55 | 55 − 65 | 65 − 75 | 75 − 85 | 85 − 95 |
| Number of cities | 3 | 10 | 11 | 8 | 3 |
Find the mean of each of the following frequency distributions
| Class interval | 0 - 6 | 6 - 12 | 12 - 18 | 18 - 24 | 24 - 30 |
| Frequency | 7 | 5 | 10 | 12 | 6 |
Which of the following cannot be determined graphically?
If the arithmetic mean of x, x + 3, x + 6, x + 9, and x + 12 is 10, the x =
If the arithmetic mean, 7, 8, x, 11, 14 is x, then x =
If the mean of observation \[x_1 , x_2 , . . . . , x_n is x\] then the mean of x1 + a, x2 + a, ....., xn + a is
| xi | fi | fixi |
| 4 | 10 | A ______ |
| 8 | 11 | B ______ |
| 12 | 9 | C ______ |
| 16 | 13 | D ______ |
| `sumf_ix_i =` ______ |
Find the value of `sumf_ix_i`
Calculate the mean of the scores of 20 students in a mathematics test:
| Marks | 10 – 20 | 20 – 30 | 30 – 40 | 40 – 50 | 50 – 60 |
| Number of students |
2 | 4 | 7 | 6 | 1 |
Find the values of x and y if the mean and total frequency of the distribution are 25 and 50 respectively.
| Class Interval | 0 – 10 | 10 – 20 | 20 – 30 | 30 – 40 | 40 – 50 | 50 – 60 |
| Frequency | 7 | x | 5 | y | 4 | 2 |
Find the mean of the following data using assumed mean method:
| Class | 0 – 5 | 5 – 10 | 10 – 15 | 15 – 20 | 20 – 25 |
| Frequency | 8 | 7 | 10 | 13 | 12 |
