Advertisements
Advertisements
प्रश्न
The contents of 100 match boxes were checked to determine the number of matches they contained.
| No. of matches | 35 | 36 | 37 | 38 | 39 | 40 | 41 |
| No. of boxes | 6 | 10 | 18 | 25 | 21 | 12 | 8 |
- Calculate, correct to one decimal place, the mean number of matches per box.
- Determine, how many extra matches would have to be added to the total contents of the 100 boxes to bring the mean up to exactly 39 matches.
उत्तर
| No. of matches (x) |
No. of boxes (f) |
fx |
| 35 | 6 | 210 |
| 36 | 10 | 360 |
| 37 | 18 | 666 |
| 38 | 25 | 950 |
| 39 | 21 | 819 |
| 40 | 12 | 480 |
| 41 | 8 | 328 |
| Total | 100 | 3813 |
i. `barx = (sumfx)/(sumf)`
= `3813/100`
= 38.13
ii. In the second case,
New mean = 39 matches
Total contents = 39 × 100 = 3900
But total number of matches already given = 3813
Number of new matches to be added = 3900 – 3813 = 87
APPEARS IN
संबंधित प्रश्न
The mean of the following distribution is 52 and the frequency of class interval 30-40 is ‘f’. Find ‘f’.
| Class Interval | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 |
| Frequency | 5 | 3 | f | 7 | 2 | 6 | 13 |
If the mean of 6, 4, 7, ‘a’ and 10 is 8. Find the value of ‘a’
From the data given below, calculate the mean wage, correct to the nearest rupee.
| Category | A | B | C | D | E | F |
| Wages (Rs/day) | 50 | 60 | 70 | 80 | 90 | 100 |
| No. of workers | 2 | 4 | 8 | 12 | 10 | 6 |
- If the number of workers in each category is doubled, what would be the new mean wage?
- If the wages per day in each category are increased by 60%; what is the new mean wage?
- If the number of workers in each category is doubled and the wages per day per worker are reduced by 40%, what would be the new mean wage?
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
Find the mode of the following data:
7, 9, 8, 7, 7, 6, 8, 10, 7 and 6
Find the median of the following:
11, 8, 15, 5, 9, 4, 19, 6, 18
Find the mean of x + 3, x + 5, x + 7, x + 9 and x + 11.
The mean of a certain number of observations is 32. Find the resulting mean, if the observation is, multiplied by 2
The mean of 5 numbers is 27. If one new number is included, the new mean is 25. Find the included number.
Find the mean of: 7, 5, 0, 3, 0, 6, 0, 9, 1 and 4
