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.