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प्रश्न
The histogram below represents the scores obtained by 25 students in a mathematics mental test. Use the data to:
- Frame a frequency distribution table.
- To calculate mean.
- To determine the Modal class.
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उत्तर
i.
| Class interval | Frequency |
| 0 – 10 | 2 |
| 10 – 20 | 5 |
| 20 – 30 | 8 |
| 30 – 40 | 4 |
| 40 – 50 | 6 |
ii.
| Class interval | Frequency (f) | Mean value (x) | fx |
| 0 – 10 | 2 | 5 | 10 |
| 10 – 20 | 5 | 15 | 75 |
| 20 – 30 | 8 | 25 | 200 |
| 30 – 40 | 4 | 35 | 140 |
| 40 – 50 | 6 | 45 | 270 |
| `sumf = 25` | `sumf = 695` |
∴ Mean = `(sumfx)/(sumf)`
= `695/25`
= 27.8
iii. Here the maximum frequency is 8 which is corresponding to class 20 – 30.
Hence, the modal class is 20 – 30.
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संबंधित प्रश्न
The marks scored by students in Mathematics in a certain Examination are given below:
| Marks Scored | Number of Students |
| 0 — 20 | 3 |
| 20 — 40 | 8 |
| 40 — 60 | 19 |
| 60 — 80 | 18 |
| 80 — 100 | 6 |
Draw histogram for the above data.
The age groups and the number of persons in the age groups, who donated blood in blood donation camp is given below. Find the measures of central angles to show the information by a pie diagram.
| Age group (Years) | 20-25 | 25-30 | 30-35 | 35-40 |
| No of persons | 80 | 60 | 35 | 25 |
Draw a histogram of the following data:
| Class interval: | 10−15 | 15−20 | 20−25 | 25−30 | 30−35 | 34−40 |
| Frequency: | 30 | 98 | 80 | 58 | 29 | 50 |
Draw a histogram for the daily earnings of 30 drug stores in the following table:
| Daily earnings (in Rs): | 450−500 | 500−550 | 550−600 | 600−650 | 650−700 |
| Numbers of stores: | 16 | 10 | 7 | 3 | 1 |
Draw a histogram for the following frequency distribution.
|
Use of electricity (Unit)
|
50 - 70 | 70 - 90 | 90 - 110 | 110 - 130 | 130 - 150 | 150 - 170 |
| No. of families | 150 | 400 | 460 | 540 | 600 | 350 |
Following table present educational level (middle stage) of females in Arunachal pradesh according to 1981 census:
| Age group | Number of females (to the nearest ten) |
| 10 - 14 | 300 |
| 15 - 19 | 980 |
| 20 - 24 | 800 |
| 25 - 29 | 380 |
| 30 - 34 | 290 |
Draw a histogram to represent the above data.
The time taken, in seconds, to solve a problem for each of 25 persons is as follows:
| 16 | 20 | 26 | 27 | 28 |
| 30 | 33 | 37 | 38 | 40 |
| 42 | 43 | 46 | 46 | 47 |
| 48 | 49 | 50 | 53 | 58 |
| 59 | 60 | 64 | 52 | 20 |
(i) Construct a frequency distribution for these data using a class interval of 10 seconds.
(ii) In a school the weekly pocket money of 50 students is as follow's:
| Weekly pocket money (₹) | No. of student |
| 40 - 50 | 2 |
| 59 - 60 | 8 |
| 60 - 70 | 12 |
| 70 - 80 | 14 |
| 80 - 90 | 8 |
| 90 - 100 | 6 |
Draw a histogram and a frequency polygon on the same graph. Find mode from the graph.
Identify the following data can be represented in a histogram?
The number of votes polled from 7 am to 6 pm in an election
Histogram is a graphical representation of ___________ data
The top speeds of thirty different land animals have been organised into a frequency table. Draw a histogram for the given data.
| Maximum Speed (km/h) | Frequency |
| 10 – 20 | 5 |
| 20 – 30 | 5 |
| 30 – 40 | 10 |
| 40 – 50 | 8 |
| 50 – 60 | 0 |
| 60 – 70 | 2 |
