RD Sharma Solutions (Part - 1)- Ex-22.1, Data Handling I Collection Organisation Data, Class 7 | RD Sharma Solutions for Class 7 Mathematics PDF Download

Question 1:

Define the following terms:
 (i) Observations
 (ii) data
 (iii) Frequency of an observation
 (iv) Frequency distribution

Answer 1:

(i) Observation : is the activity of paying close attention to someone or something in order to get information in numerical form.
(ii)Data : The collection of observations is known as data.
(iii)Frequency of an observation : The number of times an observation occurs in a given data is called the frequency of an observation.
(iv)Frequency Distribution : It is a method of presenting raw data in a form that can be easily understood.

Question 2:

The final marks in mathematics of 30 students are as follows:

(i) Arrange these marks in the ascending order. 30 to 39 one group, 40 to 49 second group, etc.
 (ii) What is the highest score?
 (iii) What is the lowest score?
 (iv) What is the range?
 (v) If 40 is the pass mark how many have failed?
 (vi) How many have scored 75 or more?
 (vii) Which observations between 50 and 60 have not actually appeared?
 (viii) How many have scored less than 50?

Answer 2:

(i) Ascending order of the numbers in groups :
(30-39):  37, 39
(40 - 49):   44, 48, 48
(50 - 59) :  50,52, 53, 55, 56, 58, 58, 59
(60 - 69) : 60, 60, 60, 61, 62, 64,   67, 68
(70 - 79) : 70, 75, 77, 78
(80 - 89) :  84, 88
(90 - 99) :  90, 98
(100-109): 100


(ii) The highest score is 100.
(iii) The lowest score is 37.
(iv) Range is = Maximum observation - Minimum observation.
                     = 100 - 37 = 63.
(v) If 40 is the pass mark, then only 2 students have failed.
(vi) 8 students have scored 75 or more.
(vii) 51, 54 and 57 are not there between 50 and 60.
(viii) 5 students scored less than 50.

Question 3:

The weights of new born babies (in kg) in a hospital on a particular day are as follows:

.3, 2.2, 2.1, 2.7, 2.6, 3.0, 2.5, 2.9, 2.8, 3.1, 2.5, 2.8, 2.7, 2.9, 2.4
 

(i) Rearrange the weights in descending order.
 (ii) Determine the highest weight.
 (iii) Determine the lowest weight.
 (iv) Determine the range.
 (v) How many babies were born on that day?
 (vi) How many babies weigh below 2.5 kg?
 (vii) How many babies weigh more than 2.8?
 (viii) How many babies weigh 2.8 kg?

Answer 3:

(i) Weights in descending order :
3.1, 3.0, 2.9, 2.9, 2.8, 2.8, 2.7, 2.7, 2.6, 2.5, 2.5, 2.4, 2.3, 2.2, 2.1
(ii) Highest weight: 3.1 Kg.
(iii) Lowest weight: 2.1 Kg.
(iv) Range = Maximum observation - Minimum observation
                 = (3.1-2.1) kg =  1.0 Kg.
(v) A total of 15 babies were born on that day.
(vi) 4 babies weigh below 2.5 kg.
(vii) 4 babies weigh more than 2.8kg.
(viii) 2 babies weigh 2.8 kg.

Question 4:

Following data gives the number of children in 40 families:

Represent it in the form of a frequency distribution.

Answer 4:

Required frequency-distribution table :

Question 5:

Prepare a frequency table of the following scores obtained by 50 students in a test:

Answer 5:

Frequency Table is :

Question 6:

A die was thrown 25 times and following scores were obtained:

Prepare a frequency table of the scores.

Answer 6:

Frequency Table is :