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प्रश्न
Find the correct answer from the alternatives given.
The formula to find mean from a grouped frequency table is \[X = A + \frac{\sum f_i u_i}{\sum f_i} \times hg\] .
विकल्प
\[\frac{x_i + A}{g}\]
\[\left( x_i - A \right)\]
\[\frac{x_i - A}{g}\]
- \[\frac{A - x_i}{g}\]
उत्तर
To find mean of a grouped frequency table using
In this formula, \[u_i = \frac{x_i - A}{g}\]
संबंधित प्रश्न
Consider the following distribution of daily wages of 50 worker of a factory.
|
Daily wages (in Rs) |
100 − 120 |
120 − 140 |
140 −1 60 |
160 − 180 |
180 − 200 |
|
Number of workers |
12 |
14 |
8 |
6 |
10 |
Find the mean daily wages of the workers of the factory by using an appropriate method.
A class teacher has the following absentee record of 40 students of a class for the whole term. Find the mean number of days a student was absent.
| Number of days | 0 - 6 | 6 - 10 | 10 -14 | 14 -20 | 20 -28 | 28 -38 | 38 -40 |
| Number of students | 11 | 10 | 7 | 4 | 4 | 3 | 1 |
Calculate the mean for the following distribution:-
| x | 5 | 6 | 7 | 8 | 9 |
| f | 4 | 8 | 14 | 11 | 3 |
Find the value of p for the following distribution whose mean is 16.6
| x | 8 | 12 | 15 | P | 20 | 25 | 30 |
| f | 12 | 16 | 20 | 24 | 16 | 8 | 4 |
The marks obtained out of 50, by 102 students in a Physics test are given in the frequency table below:
| Marks(x) | 15 | 20 | 22 | 24 | 25 | 30 | 33 | 38 | 45 |
| Frequency (f) | 5 | 8 | 11 | 20 | 23 | 18 | 13 | 3 | 1 |
Find the average number of marks.
The following distribution gives the number of accidents met by 160 workers in a factory during a month.
| No. of accidents(x) | 0 | 1 | 2 | 3 | 4 |
| No. of workers (f) | 70 | 52 | 34 | 3 | 1 |
Find the average number of accidents per worker.
Find the mean of each of the following frequency distributions
| Class interval | 0 - 10 | 10 - 20 | 20 - 30 | 30 - 40 | 40 - 50 |
| Frequency | 9 | 12 | 15 | 10 | 14 |
Find the mean of the following frequency distribution, using the assumed-mean method:
| Class | 100 – 120 | 120 – 140 | 140 – 160 | 160 – 180 | 180 – 200 |
| Frequency | 10 | 20 | 30 | 15 | 5 |
Find the arithmetic mean of the following frequency distribution using step-deviation method:
| Age (in years) | 18 – 24 | 24 – 30 | 30 – 36 | 36 – 42 | 42 – 48 | 48 – 54 |
| Number of workers | 6 | 8 | 12 | 8 | 4 | 2 |
Weight of 60 eggs were recorded as given below:
| Weight (in grams) | 75 – 79 | 80 – 84 | 85 – 89 | 90 – 94 | 95 – 99 | 100 - 104 | 105 - 109 |
| No. of eggs | 4 | 9 | 13 | 17 | 12 | 3 | 2 |
Calculate their mean weight to the nearest gram.
Which measure of central tendency is given by the x-coordinate of the point of intersection of the 'more than' ogive and 'less than' ogive?
The measurements (in mm) of the diameters of the head of the screws are given below :
| Diameter (in mm) | no. of screws |
| 33 - 35 | 9 |
| 36 - 38 | 21 |
| 39 - 41 | 30 |
| 42 - 44 | 22 |
| 45 - 47 | 18 |
Calculate the mean diameter of the head of a screw by the ' Assumed Mean Method'.
The marks obtained by a set of students in an examination all given below:
| Marks | 5 | 10 | 15 | 20 | 25 | 30 |
| Number of students | 6 | 4 | 6 | 12 | x | 4 |
Given that the mean marks of the set of students is 18, Calculate the numerical value of x.
Mean of 100 items is 49. It was discovered that three items which should have been 60, 70, 80 were wrongly read as 40, 20, 50 respectively. The correct mean is ______.
In a small scale industry, salaries of employees are given in the following distribution table:
|
Salary (in Rs.) |
4000 - 5000 |
5000 - 6000 |
6000 - 7000 |
7000 - 8000 |
8000 - 9000 |
9000 - 10000 |
|
Number of employees |
20 | 60 | 100 | 50 | 80 | 90 |
Then the mean salary of the employee is?
Consider the following distribution of SO2 concentration in the air (in ppm = parts per million) in 30 localities. Find the mean SO2 concentration using assumed mean method. Also find the values of A, B and C.
| Class interval | Frequency (fi) | Class mark (xi) | di = xi - a |
| 0.00 - 0.04 | 4 | 0.02 | -0.08 |
| 0.04 - 0.08 | 9 | 0.06 | A |
| 0.08 - 0.12 | 9 | 0.10 | B |
| 0.12 - 0.16 | 2 | 0.14 | 0.04 |
| 0.16 - 0.20 | 4 | 0.18 | C |
| 0.20 - 0.24 | 2 | 0.22 | 0.12 |
| Total | `sumf_i=30` |
An aircraft has 120 passenger seats. The number of seats occupied during 100 flights is given in the following table:
| Number of seats | 100 – 104 | 104 – 108 | 108 – 112 | 112 – 116 | 116 – 120 |
| Frequency | 15 | 20 | 32 | 18 | 15 |
An analysis of particular information is given in the following table.
| Age Group | 0 – 10 | 10 – 20 | 20 – 30 | 30 – 40 | 40 – 50 |
| Frequency | 2 | 5 | 6 | 5 | 2 |
For this data, mode = median = 25. Calculate the mean. Observing the given frequency distribution and values of the central tendency interpret your observation.
Find the mean of the following frequency distribution:
| Class | 1 – 5 | 5 – 9 | 9 – 13 | 13 – 17 |
| Frequency | 4 | 8 | 7 | 6 |
The following table gives the duration of movies in minutes:
| Duration | 100 – 110 | 110 – 120 | 120 – 130 | 130 – 140 | 140 – 150 | 150 – 160 |
| No. of movies | 5 | 10 | 17 | 8 | 6 | 4 |
Using step-deviation method, find the mean duration of the movies.
