which is a discrete random variable?

Question

Which of the following is a discrete random variable? Select all that apply. 

a) how many cats I will see before the first white one. 

b) the completed years of the next person to call me on my phone. 

c) the length of the next banana I buy when shopping. 

d) the diameter of the donuts in the cafeteria 

Answer 1

A discrete variable is something you can count. Two of these choices are countable. Which are they?