Advertisements
Advertisements
प्रश्न
Calculate the mean of the following frequency distribution :
| Class: | 10-30 | 30-50 | 50-70 | 70-90 | 90-110 | 110-130 |
| Frequency: | 5 | 8 | 12 | 20 | 3 | 2 |
उत्तर
| Class | frequency (fi) | Class mark(xi) | fixi |
| 10-30 | 5 | `(10+30)/2 = 20` | 100 |
| 30-50 | 8 | `(30+50)/2 = 40` | 320 |
| 50-70 | 12 | `(50+70)/2 = 60` | 720 |
| 70-90 | 20 | `(70+90)/2 = 80` | 1600 |
| 90-110 | 3 | `(90+110)/2 = 100` | 300 |
| 110-130 | 2 | `(110+130)/2 = 120` | 240 |
| `sumf_i = 50` | `sumf_ix_i = 3280` |
Using: Mean = `(sumf_ix_i)/(sumf_i)`
substituting the values in the formula
mean = `3280/50 = 65.6`
APPEARS IN
संबंधित प्रश्न
From the following frequency, prepare the ‘more than’ ogive.
| Score | Number of candidates |
| 400 – 450 | 20 |
| 450 – 500 | 35 |
| 500 – 550 | 40 |
| 550 – 600 | 32 |
| 600 – 650 | 24 |
| 650 – 700 | 27 |
| 700 – 750 | 18 |
| 750 – 800 | 34 |
| Total | 230 |
Also, find the median.
What is the lower limit of the modal class of the following frequency distribution?
| Age (in years) | 0 - 10 | 10- 20 | 20 -30 | 30 – 40 | 40 –50 | 50 – 60 |
| Number of patients | 16 | 13 | 6 | 11 | 27 | 18 |
The following are the ages of 300 patients getting medical treatment in a hospital on a particular day:
| Age (in years) | 10 – 20 | 20 – 30 | 30 – 40 | 40 – 50 | 50 – 60 | 60 -70 |
| Number of patients | 6 | 42 | 55 | 70 | 53 | 20 |
Form a ‘less than type’ cumulative frequency distribution.
If \[u_i = \frac{x_i - 25}{10}, \Sigma f_i u_i = 20, \Sigma f_i = 100, \text { then }\]`overlineX`
Consider the following frequency distributions
| Class | 65 - 85 | 85 - 105 | 105 - 125 | 125 - 145 | 145 - 165 | 165 - 185 | 185-205 |
| Frequency | 4 | 5 | 13 | 20 | 14 | 7 | 4 |
The difference of the upper limit of the median class and the lower limit of the modal class is?
The arithmetic mean of the following frequency distribution is 53. Find the value of k.
| Class | 0-20 | 20-40 | 40-60 | 60-80 | 80-100 |
| Frequency | 12 | 15 | 32 | k | 13 |
Change the following distribution to a 'more than type' distribution. Hence draw the 'more than type' ogive for this distribution.
| Class interval: | 20−30 | 30−40 | 40−50 | 50−60 | 60−70 | 70−80 | 80−90 |
| Frequency: | 10 | 8 | 12 | 24 | 6 | 25 | 15 |
Consider the following distribution:
| Marks obtained | Number of students |
| More than or equal to 0 | 63 |
| More than or equal to 10 | 58 |
| More than or equal to 20 | 55 |
| More than or equal to 30 | 51 |
| More than or equal to 40 | 48 |
| More than or equal to 50 | 42 |
The frequency of the class 30 – 40 is:
Find the unknown entries a, b, c, d, e, f in the following distribution of heights of students in a class:
| Height (in cm) |
Frequency | Cumulative frequency |
| 150 – 155 | 12 | a |
| 155 – 160 | b | 25 |
| 160 – 165 | 10 | c |
| 165 – 170 | d | 43 |
| 170 – 175 | e | 48 |
| 175 – 180 | 2 | f |
| Total | 50 |
Given below is a cumulative frequency distribution showing the marks secured by 50 students of a class:
| Marks | Below 20 | Below 40 | Below 60 | Below 80 | Below 100 |
| Number of students | 17 | 22 | 29 | 37 | 50 |
Form the frequency distribution table for the data.
