MEDIUM
AS and A Level
IMPORTANT
Earn 100

A biased coin is tossed times. The number of heads obtained, , follows a binomial distribution where . Find the value of and the variance of .

Important Questions on The Normal Distribution
MEDIUM
AS and A Level
IMPORTANT
A biased coin is tossed times. The number of heads obtained, , follows a binomial distribution where . Find the approximate probability of obtaining more than heads.

MEDIUM
AS and A Level
IMPORTANT
One card is selected at random from each of packs. Each pack contains cards and includes clubs. Let be the number of clubs selected from the packs. Show that the variance of is .

HARD
AS and A Level
IMPORTANT
One card is selected at random from each of packs. Each pack contains cards and includes clubs. Let be the number of clubs selected from the packs.
Obtain an approximation for the value of and justify the use of this approximation.

EASY
AS and A Level
IMPORTANT
In a large survey, of the people questioned are in full-time employment. In a random sample of of these people, find the expected number in full-time employment.

MEDIUM
AS and A Level
IMPORTANT
In a large survey, of the people questioned are in full-time employment. In a random sample of of these people, find the standard deviation of the number in full-time employment.

HARD
AS and A Level
IMPORTANT
In a large survey, of the people questioned are in full-time employment. In a random sample of of these people, find the approximate probability that fewer than half of the sample are in full-time employment.

MEDIUM
AS and A Level
IMPORTANT
A company manufactures rubber and plastic washers in the ratio . The washers are randomly packed into boxes of .
Find the probability that a randomly selected box contains exactly rubber washers.

MEDIUM
AS and A Level
IMPORTANT
A company manufactures rubber and plastic washers in the ratio . The washers are randomly packed into boxes of .
Find the probability that a randomly selected box contains exactly plastic washers.
