Question 8
A grouped frequency table with class intervals of equal sizes using 250 – 270 (270 not included in this interval) as one of the class intervals is constructed for the following data.
268, 220, 368, 258, 242, 310, 272, 342
310, 290, 300, 320, 319, 304, 402, 318
406, 292, 354, 278, 210, 240, 330, 316,
406, 215, 258, 236.
The frequency of class 310 - 330 is:
A) 4
B) 5
C) 6
D) 7
The answer is C.
Here, we arrange the given data into groups like 210 - 230, 230 - 250, ……….390 - 410.
(since our data is from 210 to 406).
The class width, in this case, is 20.
Now, the given data can be arrange in tabular form as follows.
Class intervalTally marksFrequency210−230|||3230−250|||3250−270|||3270−290||2290−310||||4310−330/|||||6330−350||2350−370||2370−390−0390−410||||3
Hence, the frequency of the class 310 - 330 is 6.