Advertisements
Advertisements
प्रश्न
Marks obtained (in mathematics) by 9 students are given below:
60, 67, 52, 76, 50, 51, 74, 45 and 56
- Find the arithmetic mean.
- If marks of each student be increased by 4; what will be the new value of arithmetic mean?
उत्तर
a. Here, n = 9,
`barx = (x_1 + x_2 + ...... + x_n)/n`
∴ `barx = (60 + 67 + 52 + 76 + 50 + 51 + 74 + 45 + 56)/9`
= `531/9`
= 59
b. If marks of each student be incresed by 4 then new arithmetic mean will be = 59 + 4 = 63
APPEARS IN
संबंधित प्रश्न
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 total marks?
Find the mean, median and mode of the following marks obtained by 16 students in a class test marked out of 10 marks:
0, 0, 2, 2, 3, 3, 3, 4, 5, 5, 5, 5, 6, 6, 7 and 8.
The marks obtained by 120 students in a mathematics test is given below:
| Marks | No. of students |
| 0 – 10 | 5 |
| 10 – 20 | 9 |
| 20 – 30 | 16 |
| 30 – 40 | 22 |
| 40 – 50 | 26 |
| 50 – 60 | 18 |
| 60 – 70 | 11 |
| 70 – 80 | 6 |
| 80 – 90 | 4 |
| 90 – 100 | 3 |
Draw an ogive for the given distributions on a graph sheet. Use a suitable scale for your ogive. Use your ogive to estimate:
- the median
- the number of student who obtained more than 75% in test.
- the number of students who did not pass in the test if the pass percentage was 40.
- the lower quartile.
The mean of the following distribution in 52 and the frequency of class interval 30-40 'f' find f
| C.I | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 |
| freq | 5 | 3 | f | 7 | 2 | 6 | 13 |
Find the mode and the median of the following frequency distributions.
| x | 10 | 11 | 12 | 13 | 14 | 15 |
| f | 1 | 4 | 7 | 5 | 9 | 3 |
In 10 numbers, arranged in increasing order, the 7th number is increased by 8, how much will the median be changed?
The rainfall (in mm) in a city on 7 days of a certain week is recorded as follows:
| Day: | Mon | Tue | Wed | Thus | Fri | Sat | Sun |
| Rainfall (in mm): | 0.5 | 2.7 | 2.6 | 0.5 | 2 | 5.8 | 1.5 |
Find the total and average (mean) rainfall for the week.
Find the mean of: first six even natural numbers
The median of first ten even natural numbers is ___________
For the given data given below, calculate the mean of its median and mode.
6, 2, 5, 4, 3, 4, 4, 2, 3
