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प्रश्न
Compute mean from the following data:
| Marks | 0 – 7 | 7 – 14 | 14 – 21 | 21 – 28 | 28 – 35 | 35 – 42 | 42 – 49 |
| Number of Students | 3 | 4 | 7 | 11 | 0 | 16 | 9 |
उत्तर
| Class | Frequency (f) | Cumulative Frequency (cf) |
| 0 – 7 | 3 | 3 |
| 7 – 14 | 4 | 7 |
| 14 – 21 | 7 | 14 |
| 21 - 28 | 11 | 25 |
| 28 – 35 | 0 | 25 |
| 35 – 42 | 16 | 41 |
| 42 – 49 | 9 | 50 |
| N = Σ𝑓 = 50 |
Now, N = 50 ⇒ `N/2` = 25.
The cumulative frequency just greater than 25 is 41 and the corresponding class is 35 – 42.
Thus, the median class is 35 – 42.
∴ l = 35, h = 7, f = 16, cf = c.f. of preceding class = 25 and `N/2` = 25.
Now,
Median =` l +((N/2−c_f)/f) × h`
Median `= 35 + ((25 − 25)/16) xx 7`
= 35 + 0
= 35
Hence, the median age is 35 years.
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संबंधित प्रश्न
A life insurance agent found the following data for distribution of ages of 100 policy holders. Calculate the median age, if policies are given only to persons having age 18 years onwards but less than 60 years.
| Age (in years) | Number of policy holders |
| Below 20 | 2 |
| 20 - 25 | 4 |
| 25 - 30 | 18 |
| 30 - 35 | 21 |
| 35 - 40 | 33 |
| 40 - 45 | 11 |
| 45 - 50 | 3 |
| 50 - 55 | 6 |
| 55 - 60 | 2 |
Calculate the missing frequency from the following distribution, it being given that the median of distribution is 24.
| Class | 0 – 10 | 10 – 20 | 20 – 30 | 30 – 40 | 40 - 50 |
| Frequency | 5 | 25 | ? | 18 | 7 |
If the median of the following frequency distribution is 32.5, find the values of `f_1 and f_2`.
| Class | 0 – 10 | 10 – 20 | 20 – 30 | 30 -40 | 40 – 50 | 50 – 60 | 60 – 70 | Total |
| Frequency | `f_1` |
5 |
9 | 12 | `f_2` | 3 | 2 | 40 |
Find the median from the following data:
| Class | 1 – 5 | 6 – 10 | 11 – 15 | 16 – 20 | 21 – 25 | 26 – 30 | 31 – 35 | 35 – 40 | 40 – 45 |
| Frequency | 7 | 10 | 16 | 32 | 24 | 16 | 11 | 5 | 2 |
If 35 is removed from the data, 30, 34, 35, 36, 37, 38, 39, 40 then the median increases by ______.
The abscissa of the point of intersection of the less than type and of the more than type cumulative frequency curves of a grouped data gives its ______.
Consider the data:
| Class | 65 – 85 | 85 – 105 | 105 – 125 | 125 – 145 | 145 – 165 | 165 – 185 | 185 – 205 |
| Frequency | 4 | 5 | 13 | 20 | 14 | 7 | 4 |
The difference of the upper limit of the median class and the lower limit of the modal class is:
Will the median class and modal class of grouped data always be different? Justify your answer.
Find the median of the following distribution:
| Marks | 0 – 10 | 10 –20 | 20 – 30 | 30 – 40 | 40 – 50 | 50 – 60 |
| Number of students | 5 | 8 | 20 | 15 | 7 | 5 |
The following table gives the monthly consumption of electricity of 100 families:
| Monthly Consumption (in units) |
130 – 140 | 140 – 150 | 150 – 160 | 160 – 170 | 170 – 180 | 180 – 190 | 190 – 200 |
| Number of families |
5 | 9 | 17 | 28 | 24 | 10 | 7 |
Find the median of the above data.
