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प्रश्न
Find the mean of x + 3, x + 5, x + 7, x + 9 and x + 11.
उत्तर
Mean of x + 3, x + 5, x + 7, x + 9 and x + 11
∴ Mean =`(("x"+3)("x"+5)("x"+7)("x"+9)("x"+11))/2` ..........(Here n = 5)
= `(5"x"+35)/5`
= `(5("x"+7))/5`
= x + 7
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संबंधित प्रश्न
If each number given in (a) is diminished by 2, find the new value of mean.
The following are the marks obtained by 70 boys in a class test:
| Marks | No. of boys |
| 30 – 40 | 10 |
| 40 – 50 | 12 |
| 50 – 60 | 14 |
| 60 – 70 | 12 |
| 70 – 80 | 9 |
| 80 – 90 | 7 |
| 90 – 100 | 6 |
Calculate the mean by:
Short-cut method
The mean of the following distribution is 62.8 and the sum of all the frequencies is 50. Find the missing frequencies f1 and f2.
| Class | 0 – 20 | 20 – 40 | 40 – 60 | 60 – 80 | 80 – 100 | 100 – 120 |
| Frequency | 5 | f1 | 10 | f2 | 7 | 8 |
Find the mode of the following data:
9, 11, 8, 11, 16, 9, 11, 5, 3, 11, 17 and 8
A boy scored following marks in various class tests during a term; each test being marked out of 20.
15, 17, 16, 7, 10, 12, 14, 16, 19, 12 and 16
What are his modal marks?
Draw an ogive for the data given below and from the graph determine:
- the median marks
- the number of students who obtained more than 75% marks
| Marks | No. of students |
| 0 – 9 | 5 |
| 10 – 19 | 9 |
| 20 – 29 | 16 |
| 30 – 39 | 22 |
| 40 – 49 | 26 |
| 50 – 59 | 18 |
| 60 – 69 | 11 |
| 70 – 79 | 6 |
| 80 – 89 | 4 |
| 90 – 99 | 3 |
Find the arithmetic mean (correct to the nearest whole number) by using step-deviation method.
| x | 5 | 10 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 |
| f | 20 | 43 | 75 | 67 | 72 | 45 | 39 | 9 | 8 | 6 |
In a basket there are 10 tomatoes. The weight of each of these tomatoes in grams is as follows:
60, 70, 90, 95, 50, 65, 70, 80, 85, 95.
Find the median of the weights of tomatoes.
The mean of 5 numbers is 27. If one new number is included, the new mean is 25. Find the included number.
Find the median of the following sets of numbers.
25, 11, 15, 10, 17, 6, 5, 12.
