Question 4
The width of each of five continuous classes in a frequency distribution is 5 and the lower class limit of the lowest class is 10. The upper class limit of the highest class is:
A) 15
B) 25
C) 35
D) 40
Let x and y be the upper and lower class limit of the frequency distribution.
Given, width of the class = 5
⇒x−y=5…(i)
Also, given lower class (y) = 10.
On putting y = 10 in (i), we get,
x–10=5⇒x=15
so, the upper class limit of the lowest class is 15.
Hence, the upper class limit of the highest class
=Number of continuous classes×class width+lower class limit of the lowest class
=5×5+10=25+10=35
Hence, the upper class limit of the highest class is 35.
Alternate Method:
After finding the upper class limit of the lowest class, the five continuous classes in a frequency distribution with width 5 are 10 - 15, 15 - 20, 20 - 25, 25 - 30, and 30 - 35.
Hence, the upper limit of this class is 35.