Using the $2^k$ n rule, determine the number of classes needed for the following data set sizes.

a$)n=100$

b$)n=400$

c$)n=1500$

d$)n=2500$

a$)$ The number of classes needed when $n=100$ is

b$)$ The number of classes needed when $n=400$ is

c$)$ The number of classes needed when $n=1500$ is

d$)$ The number of classes needed when $n=2500$ is