Case Study

The following data gives the weights (in grams) of some marbles picked up randomly from 3 boxes. The data was presented in the tabular form as below:

Based on the above information, answer the following questions:

1. Class size of the given distribution is :
   (a) 5
   (b) 10
   (c) 50
   (d) 85

2. Class mark of the 3rd class is :
   (a) 60
   (b) 65
   (c) 125
   (d) 62.5

3. The number of marbles whose weight is more than or equal to 75 g is :
   (a) 0
   (b) 1
   (c) 2
   (d) 28

4. The number of marbles whose weight is less than 70 g is :
   (a) 26
   (b) 28
   (c) 4
   (d) 2

5. The class boundaries of the class 7th class interval are :
   (a) 80, 85
   (b) 80.5, 85.5
   (c) 79.5, 85.5
   (d) 80, 85.5

Assertion (A) : Classes of the form : 1-10, 11-20, 21-30 etc. are said to be in inclusive form.

Reason (R) : A frequency distribution in which each upper limit as well as lower limit is included is called an inclusive form.

1. A is true, R is false

2. A is false, R is true

3. Both A and R are true

4. Both A and R are false

Age of teachers of a school varies from 24 years to 72 years. Rishabh has to make a grouped frequency distribution table of age of teachers. Which among the following class intervals of age will be most appropriate to make meaningful conclusion in less time and effort?

1. 24 - 26, 26 - 28, 28 - 30, and so on

2. 24 - 30, 30 - 36, 36 - 42, and so on

3. 24 - 48, 48 - 72

4. none of these

The distribution of marks of students of a class in a test is shown in the table below.

Which of the following statements are correct?

(i) We can definitely say that no one scored 60 marks.

(ii) The number of students who got at least 30 marks is 12.

1. only (i)

2. only (ii)

3. both (i) and (ii)

4. none of these