Question

The weight in grams of 35 mangoes picked at random from a consignment are as follows:

131, 113, 82, 75, 204, 81, 84, 118, 104, 110, 79, 107, 111, 141, 136, 123, 90, 78, 90, 115, 110, 98, 106, 99, 107, 84, 76, 186, 82, 100, 109, 128, 115, 107, 115 .

Form a grouped frequency table by dividing the data into classes of equal width of 20 g, such that the mid-value (Class mark) of the first class interval is 70g.

Answer 1

It is given that the size of each class interval = 20 and the mid-value of the first class interval is 70.
Let the lower limit of the first class interval be a, then its upper limit = a + 20.
(a+a+20)/2 = 70
⇒ a = 70 – 10 = 60
Thus, the first class interval is 60 – 80 and the other class-intervals are 80 – 100, 100 – 120, 120 – 140, 140 – 160, 160 – 180, 180 – 200 and 200 – 220.
So, the grouped frequency table is as under: