New Zealand
Level 8 - NCEA Level 3

# Discrete Random Variable

## Interactive practice questions

A coin is tossed three times and the total number of tails is recorded.

a

Can this experiment be represented by a discrete random variable?

Yes

A

No

B

Yes

A

No

B
b

If $X$X represents the number of possible tails in the three coin tosses, list all the possible outcomes of the experiment.

Write all the outcomes on the same line, separated by commas.

Easy
Less than a minute

On a popular TV cooking show, contestants are to randomly choose a blue, red or yellow serviette from a box to split themselves into random cooking teams.

The number of pears on each pear tree in an orchard is recorded.

The weights of babies born in a local hospital in the last month have been recorded. One midwife is interested in the probability that the next baby born would weigh more than $2.8$2.8 kg.

### Outcomes

#### S8-4

Investigate situations that involve elements of chance: A calculating probabilities of independent, combined, and conditional events B calculating and interpreting expected values and standard deviations of discrete random variables C applying distributions such as the Poisson, binomial, and normal

#### 91586

Apply probability distributions in solving problems