To represent the given data by a bar-graph, draw two axes perpendicular to each other. Now, represent ‘Months’ on OX and ‘Number of watch sold’ on OY. Erect rectangles of the same width. The heights of the rectangles are proportional to number of watches, using a suitable scale:
Here, scale is 1 cm = 500 watches
Since 500 watches = 1 cm
1000 watches = 2 cm
1500 watches = 3 cm
2000 watches = 4 cm
2500 watches = 5 cm
(i) What is the size of the class intervals?
(ii) Which class has the highest frequency?
(iii) Which class has the lowest frequency?
(iv) What is the upper limit of the class interval 250-275?
(v) Which two classes have the same frequency?
(i) Class size = [Upper class limit] - [Lower class limit] = 125 - 100 = 25.
(ii) The class 200-225 is having the highest frequency (which is 140).
(iii) The class 300-325 is having the lowest frequency (which is 20).
(iv) The upper limit of the class interval 250-275 is 275.
(v) The classes (150–175) and (225-250) are having the same frequency (which is 55).