A discrete random variable is a random variable with a specific and countable set of possible values.
A continuous random variable is used to represent all of the possible values in a particular interval.
Which of the following are discrete random variables and which are continuous random variables?
distance around a randomly chosen lake
number of socks in a drawer
height of a randomly chosen child
weight of a randomly chosen rock from a pile
number of hours worked
temperature of water in a pool
number of defective tires in a production line
volume of water in a pool