Question

The daily wages of workers in a construction unit were recorded as follows:

Class Marks (Wages)	425	275	525	575	625	675
No. of workers	6	12	15	17	7	13

Form a frequency distribution table with class intervals and find modal wage by plotting a histogram.

Answer 1

Difference between two consecutive class marks = 475 – 425 = 50.

Adjustment factor = `"Class width"/2`

= `50/2`

= 25

Lower class limit = Class mark – Adjustment factor

Upper class limit = Class mark + Adjustment factor

Class	Frequency
400 – 450	6
450 – 500	12
500 – 550	15
550 – 600	17
600 – 650	7
650 – 700	3

Steps of construction:

1. Take 2 cm along x-axis = ₹ 50 and 2 cm along y-axis = 5 workers.

2. Construct rectangles corresponding to the given data.

3. In highest rectangle, draw two st. lines AD and BC from corners of the rectangles on either side of the highest rectangle to the opposite corners of the highest rectangle.

4. Let K be the point of intersection of AD and BC. Through K, draw a vertical line to meet the x-axis at L. The abscissa of the point L represents 557.50.

Hence, mode = ₹ 557.50