EASY
AS and A Level
IMPORTANT
Earn 100

A pack of five DVDs contains three movies and two documentaries. Three DVDs are selected and the following table shows the probability distribution for M, the number of movies selected.

m 1 2 3
PM=m 0.3 0.6 0.1

Draw up the probability distribution table for D, the number of documentaries selected.

Important Questions on Probability Distributions

EASY
AS and A Level
IMPORTANT
In a particular country, 40% of the population is right-handed and 40% of the population has red hair. Two people are randomly selected from the population. Draw up the probability distribution for X, the number of right-handed, red-haired people selected, and state what assumption must be made in order to do this.
EASY
AS and A Level
IMPORTANT

A fair 4 -sided die, numbered 1, 2, 3 and 5, is rolled twice. The random variable X is the sum of the two numbers on which the die comes to rest.

Show that PX=8=18

EASY
AS and A Level
IMPORTANT

A fair 4 -sided die, numbered 1, 2, 3 and 5, is rolled twice. The random variable X is the sum of the two numbers on which the die comes to rest.

Draw up the probability distribution table for X.

EASY
AS and A Level
IMPORTANT

There are eight letters in a post box, and five of them are addressed to Mr Nut. Mr Nut removes four letters at random from the box.

Find the probability that none of the selected letters are addressed to Mr Nut.

EASY
AS and A Level
IMPORTANT

There are eight letters in a post box, and five of them are addressed to Mr Nut. Mr Nut removes four letters at random from the box.

Draw up the probability distribution table for N, the number of selected letters that are addressed to Mr Nut.

EASY
AS and A Level
IMPORTANT

There are eight letters in a post box, and five of them are addressed to Mr Nut. Mr Nut removes four letters at random from the box.

Describe one significant feature of a vertical line graph or bar chart that could be used to represent the probability distribution for N.

EASY
AS and A Level
IMPORTANT
A discrete random variable Y is such that Y8, 9, 10. Given that PY=y=ky, find the value of the constant k.
EASY
AS and A Level
IMPORTANT

θ is a discrete random variable and θ3, 4, 5, 6. Given that Pθ=q=cq2 find the value of the constant c.