Advertisements
Advertisements
प्रश्न
Find the mean of the following frequency distribution by the step deviation method :
| Class | 100-110 | 110-120 | 120-130 | 130-140 | 140-150 |
| Frequency | 15 | 18 | 32 | 25 | 10 |
उत्तर
| Class Interval | xi | fi | A = 125 `"u" = ("x - A")/"h"_"i"` |
fiu |
| 100-110 | 105 | 15 | -2 | -30 |
| 110-120 | 115 | 18 | -1 | -18 |
| 120-130 | A = 125 | 32 | 0 | 0 |
| 130-140 | 135 | 25 | 1 | 25 |
| 140-150 | 145 | 10 | 2 | 20 |
| Total | 100 | -3 |
A=125 and hi = 10
`barx = A + "h" xx (Σf_i "u")/(Σf_i)`
`barx = 125 + 10 xx (-3)/100`
`barx = 125-0.3`
`barx = 124.70`
∴ Mean = 124.70
APPEARS IN
संबंधित प्रश्न
Calculate the mean of the distribution given below using the shortcut method.
| Marks | 11-20 | 21-30 | 31-40 | 41-50 | 51-60 | 61-70 | 71-80 |
| No. of students | 2 | 6 | 10 | 12 | 9 | 7 | 4 |
Find mean by step-deviation method:
| C.I. | 63 – 70 | 70 – 77 | 77 – 84 | 84 – 91 | 91 – 98 | 98 – 105 | 105 – 112 |
| Frequency | 9 | 13 | 27 | 38 | 32 | 16 | 15 |
Attempt this question on a graph paper. The table shows the distribution of marks gained by a group of 400 students in an examination.
|
Marks (Less than ) |
10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 |
| No.of student | 5 | 10 | 30 | 60 | 105 | 180 | 270 | 355 | 390 | 400 |
Using scaie of 2cm to represent 10 marks and 2 cm to represent 50 student, plot these point and draw a smooth curve though the point
Estimate from the graph :
(1)the median marks
(2)the quartile marks.
Find the mode of following data, using a histogram:
| Class | 0 – 10 | 10 – 20 | 20 – 30 | 30 – 40 | 40 – 50 |
| Frequency | 5 | 12 | 20 | 9 | 4 |
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.
Using a graph paper, draw an ogive for the following distribution which shows a record of the width in kilograms of 200 students.
| Weight | Frequency |
| 40 – 45 | 5 |
| 45 – 50 | 17 |
| 50 – 55 | 22 |
| 55 – 60 | 45 |
| 60 – 65 | 51 |
| 65 – 70 | 31 |
| 70 – 75 | 20 |
| 75 – 80 | 9 |
Use your ogive to estimate the following:
- The percentage of student weighting 55 kg or more
- The weight above which the heaviest 30% of the student fall
- The number of students who are
- underweight
- overweight, If 55.70 kg is considered as standard weight.
Following 10 observations are arranged in ascending order as follows.
2, 3, 5, 9, x + 1, x + 3, 14, 16, 19, 20
If the median of the data is 11, find the value of x.
Find the median of the following:
11, 8, 15, 5, 9, 4, 19, 6, 18
The pocket expenses (per day) of Anuj, during a certain week, from Monday to Saturday were ₹85.40, ₹88.00, ₹86.50, ₹84.75, ₹82.60 and ₹87.25. Find the mean pocket expenses per day.
Find the median of the given data: 36, 44, 86, 31, 37, 44, 86, 35, 60, 51
