The weekly wages (in rupees) of 28 workers of a factory are given below,
668, 610, 642, 658, 668, 620, 719, 720, 700, 690, 710, 642, 672, 654, 692, 706, 718, 702, 704, 678, 615, 640, 680, 716, 705, 615, 636, 656.
Construct in frequency table with equal class intervals, taking the first of the class intervals as 610-630, where 630 is not included.

The electricity bills (in rupees) of 25 houses of a certain locality for a month are given below: 324, 700, 617, 400, 356, 365, 435, 506, 548, 738, 780, 378, 570, 685, 312, 630, 584, 674, 754, 776, 596, 747, 565, 763, 472. Arrange the above data in increasing order and form a frequency table using equal class intervals, starting from 300-400, where 400 is not included.

The daily earnings (in rupees) of 24 stores in a market was recorded as under: 715, 650, 685, 550, 574, 530, 610, 525, 742, 680, 736, 524, 500, 585, 723, 545, 532, 560,, 580, 545, 625, 630, 645, 700. Prepare a frequency table taking equal class sizes. one such class is 500-550, where 550 is not included.