Here, = 11 + 12 = 23
And 33 + q = 46
⇒ q = 46 − 33
= 13
Thus, p is 23 and q is 13.
Now,
Here the maximum class frequency is 20, and the class corresponding to this frequency is 500-600.
So, the modal class is 500-600.
Also, Σ f = N = 80
⇒ \(\frac{N}2\) = 40.
The cumulative frequency just greater than 40 is 46, and the corresponding class is 400- 500.
Thus, the median class is 400 - 500.