Which of these is a discrete random variable?

The height of a student picked at randomCorrect answerYour answerThe number of heads in 5 tosses of a coinCorrect answerYour answerThe time a runner takes for 100 mCorrect answerYour answerThe weight of a parcel at a post officeCorrect answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer B

Correct answer: B

A discrete random variable takes separate, countable values; a continuous one can take any value in an interval.
The number of heads can only be 0, 1, 2, 3, 4 or 5. Height, time and weight are measured, and can take any value in a range.

Worth noting

Time is recorded to a few decimals, but it can take any value in between: it is continuous.

Concept: Discrete and continuous random variables
Typical timeTypical: 60 s
Your timeYours: —

The rule this testsRandom variables

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Ten questions from Random Variables, Expectation & Variance, at your own pace.

Which of these is a discrete random variable?

Explanation