The following marks were obtained by the students in a test :

81, 72, 90, 90, 86, 85, 92, 70, 71, 83, 89, 95, 85, 79, 62.

The range of marks is :

1. 9

2. 17

3. 27

4. 33

The width of each of nine classes in a frequency distribution is 2.5 and the lower class boundary of the lowest class is 10.6. Which of the following is the upper class boundary of the highest class?

1. 28.1

2. 30.6

3. 33.1

4. 35.6

A frequency polygon is constructed by plotting frequency of the class interval and the :

1. upper limit of the class

2. lower limit of the class

3. either (a) or (b)

4. mid-value of the class

In a histogram, the area of each rectangle is proportional to :

1. the class-mark of the corresponding class-interval

2. the class-size of the corresponding class-interval

3. frequency of the corresponding class-interval

4. cumulative frequency of the corresponding class interval