Which of the following is NOT an example of a discrete random variable?

Question

Which of the following is NOT an example of a discrete random variable?

X = Total steps walked in a day

X = Number of flights that arrive in Edmonton in a day

X = Number of bedrooms in a house

X = Number of people on the bus

X = Total time spent driving in a day

Answer 1

The answer is "total time spent driving in a day" because this is a continuous random variable. Remember that discrete random variables are variables where not every single number is possible. Total steps walked in a day is discrete because steps are only counted in integers; it is impossible to have a quarter of a step. The same goes for the number of flights that arrive in Edmonton in a day, the number of bedrooms in a house, and the number of people on a bus. All of these objects are counted in integers and there are no decimals, as having half of a flight, half of a bedroom, or half of a person is not practical. Time is continuous because any measure of time could be recorded, even to 10 decimal places or more.