Question

Consider the frequency distribution of the heights of 60 students of a class

Height (in cm)	No. of students	Cumulative frequency
150 – 155	16	16
155 – 160	12	28
160 – 165	9	37
165 – 170	7	44
170 – 175	10	54
175 – 180	6	60

The sum of the lower limit of the modal class and the upper limit of the median class is 

(a) 310 

(b) 315 

(c) 320 

(d) 330

Answer 1

Correct answer is (b) 315

The class having the maximum frequency is the modal class. 

So, the modal class is 150 – 155 and its lower limit is 150. 

Also, N = 60 

⇒ N/2 = 30 

The cumulative frequency just more than 30 is 37 and its class is 160 – 165, whose upper limit is 165. 

∴ Required sum = (150 + 165) = 315