HARD
Diploma
IMPORTANT
Earn 100

Ten balls of identical size are in a bag. Two of the balls are red and the rest are blue. Balls are picked out at random from the bag and are not replaced. Let R be the number of balls drawn out, up to and including the first red one. List the possible values of R and their associated probabilities.

Important Questions on Valid Comparisons and Informed Decisions: Probability Distributions

HARD
Diploma
IMPORTANT

Ten balls of identical size are in a bag. Two of the balls are red and the rest are blue. Balls are picked out at random from the bag and are not replaced. Let R be the number of balls drawn out, up to and including the first red one. Calculate the mean value of R.

MEDIUM
Diploma
IMPORTANT

Ten balls of identical size are in a bag. Two of the balls are red and the rest are blue. Balls are picked out at random from the bag and are not replaced. Let R be the number of balls drawn out, up to and including the first red one. What is the most likely value of R ?

HARD
Diploma
IMPORTANT

Consider the bag of balls in question 8 Suppose now that each ball is replaced before the next is drawn. Show that the probability of the first red being drawn out on the second go is 425.

MEDIUM
Diploma
IMPORTANT

Consider the bag of balls in question 8. Suppose now that each ball is replaced before the next is drawn. Calculate the probability that the first red is drawn after the third go.

MEDIUM
Diploma
IMPORTANT

 

7 Consider the bag of balls in question 8 Suppose now that each ball is replaced before the next is drawn. Derive a formula to find the probability that the first red is drawn on the nth go.

MEDIUM
Diploma
IMPORTANT

Consider the bag of balls in question 8 Suppose now that each ball is replaced before the next is drawn. What is the most likely value of R ?

MEDIUM
Diploma
IMPORTANT

Suppose an instant lottery ticket is purchased for $2. The possible prizes are $0, $2, $20, $200 and $1000. Let Z be the random variable representing the amount won on the ticket, and suppose Z has the following distribution.

z 0 2 20 200 1000
PZ=z   0.2 0.05 0.001 0.0001

Determine P(Z=0).

MEDIUM
Diploma
IMPORTANT

Suppose an instant lottery ticket is purchased for $2. The possible prizes are $0, $2, $20, $200 and $1000. Let Z be the random variable representing the amount won on the ticket, and suppose Z has the following distribution.

z 0 2 20 200 1000
PZ=z   0.2 0.05 0.001 0.0001

Determine E(Z) and interpret its meaning.