Consider these data on the selling prices of the latest model of cell phones in a local convenience store.

Selling Price	Frequency
120 to 150	4
150 to 180	18
150 to 210	30
210 to 240	20
240 to 270	17
270 to 300	10
300 to 330	6

a. How large is the class interval (use the 2^k> n rule)?

b. What was the total number sold?

c. How many cell phones sold for less than $21 0?

d. What is the relative frequency for the "$210 up to 240" class?

e. What is the midpoint of the "$150 up to 180" class?

f. What were the maximum and minimum selling prices?