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Data Handling

Class 8th Mathematics RS Aggarwal Solution
Exercise 21a
  1. The number of members in 20 families are given below: 4, 6, 5, 5, 4, 6, 3, 3,…
  2. A dice was thrown 30 times and the following outcomes were noted: 2, 1, 2, 4,…
  3. The following data gives the number of children in 40 families: 1, 2, 6, 5, 1,…
Exercise 21b
  1. The marks obtained by 40 students of a class in an examination are given below:…
  2. The electricity bills (in rupees) of 25 houses of a certain locality for a…
  3. The weekly wages (in rupees) of 28 workers of a factory are given below: 668,…
  4. The weekly pocket expenses (in rupees) of 30 students of a class are given…
  5. The daily earnings (in rupees) of 24 stores in a market was recorded as under:…
  6. The heights (in cm) of 22 students were recorded as under: 125, 132, 138, 144,…
Exercise 21a
Question 1.

The number of members in 20 families are given below:

4, 6, 5, 5, 4, 6, 3, 3, 5, 5, 3, 5, 4, 4, 6, 7, 3, 5, 5, 7.

Prepare a frequency distribution of the data.
Answer:

Arranging the members in ascending order, we get


3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 7, 7


The frequency distribution table is given below:
Question 2.

A dice was thrown 30 times and the following outcomes were noted:

2, 1, 2, 4, 6, 1, 2, 3, 6, 5, 4, 4, 3, 1, 1, 3, 1, 1, 5, 6, 6, 2, 2, 3, 4, 2, 5, 5, 6, 4.

Prepare a frequency table.
Answer:

Arranging the outcomes of dice in ascending order, we get


1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 6


The frequency distribution table is given below:
Question 3.

The following data gives the number of children in 40 families:
1, 2, 6, 5, 1, 5, 1, 3, 2, 6, 2, 3, 4, 2, 0, 4, 4, 3, 2, 2, 0, 0, 1, 2, 2, 4, 3 2„1, 0, 5, 1, 2, 4, 3, 4, 1, 6, 2, 2.
Represent it in the form of a frequency distribution.
Answer:

In the question, the data of the number of children in 40 familiare is given as:

1, 2, 6, 5, 1, 5, 1, 3, 2, 6, 2, 3, 4, 2, 0, 4, 4, 3, 2, 2, 0, 0, 1, 2, 2, 4, 3 2„1, 0, 5, 1, 2, 4, 3, 4, 1, 6, 2, 2.

On arranging the children in ascending order, we get,

0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 5, 5, 5, 6, 6, 6

Now, we plot this data in a frequency distribution table as given below:
Exercise 21b
Question 1.

The marks obtained by 40 students of a class in an examination are given below:

8, 47, 22, 31, 17, 13, 38, 26, 3, 34, 29, 11, 22, 7, 15, 24, 38, 31, 21, 35, 42, 24, 45, 23, 21, 27, 29, 49, 25, 48, 21, 15, 18, 27, 19, 45, 14, 34, 37, 34.

Prepare a frequency distribution table with equal class intervals, starting from 0-10 (where 10 is not included).
Answer:

The frequency distribution table is given as:
Question 2.

The electricity bills (in rupees) of 25 houses of a certain locality for a month are given below:

324, 700, 617, 400, 356, 365, 435, 506, 548, 736, 780, 378, 570, 685, 312, 630, 584, 674, 754, 776, 596, 745, 565, 763, 472.

Arrange the above data in increasing order and form a frequency table using equal class intervals, starting from 300-400, where 400 is not included.
Answer:

The frequency distribution table is given as:
Question 3.

The weekly wages (in rupees) of 28 workers of a factory are given below:

668, 610, 642, 658, 668, 620, 719, 720, 700, 690, 710, 642, 672, 654, 692, 706, 718, 702, 704, 678, 615, 640, 680, 716, 705, 615, 636, 656.

Construct a frequency table with equal class intervals, taking the first of the class intervals as 610-630, where 630 is not included.
Answer:

The frequency distribution table is given as:
Question 4.

The weekly pocket expenses (in rupees) of 30 students of a class are given below:

62, 80, 110, 75, 84, 73, 60, 62, 100, 87, 78, 94, 117, 86, 65, 68, 90, 80, 118, 72, 95, 72, 103, 96, 64, 94, 87, 85, 105, 115.

Construct a frequency table with class intervals 60-70 (where 70 is not included), 70-80, 80-90, etc.
Answer:

The frequency distribution table is given as:
Question 5.

The daily earnings (in rupees) of 24 stores in a market was recorded as under:

715, 650, 685, 550, 573, 530, 610, 525, 742, 680, 736, 524, 500; 585, 723, 545, 532, 560, 580, 545, 625, 630, 645, 700.

Prepare a frequency table taking equal class sizes. One such class is 500-550, where 550 is not included.
Answer:

The Frequency distribution will be as follows:
Question 6.

The heights (in cm) of 22 students were recorded as under:

125, 132, 138, 144, 142, 136, 134, 125, 135, 130, 126, 132, 135, 142, 143, 128, 126, 136, 135, 130, 130, 133.

Prepare a frequency distribution table, taking equal class intervals and starling from 125-130, where 130 is not included.
Answer:

The frequency distribution will be as follows