Answer:
7
Explanation:
class width=(largest value-smallest value)/k
where k is the number of classes.
According to 2^k>n rule
We choose different value of k till we get the 2^k greater than number of observation.
The given value of n=60
Now,
2^1=2 <60
2^2=4 <60
2^3=8 <60
2^4=16 <60
2^5=32 <60
2^6=64 >60
So, k=6.
Now class width=(largest value-smallest value)/k
class width=72-30/6
class width=42/6=7
class width=7
