Which of the following is a discrete random variable?

1.   ?    The number of accidents at a particular road junction each day
2.   ?    The most popular colour of car
3.   ?    The amount of time a customer has to wait in the bank
4.   ?    The height of students in a particular class

Which of the following is a continuous random variable?

1.   ?    The number of boys in a family of 3 children
2.   ?    The nationality of students in a particular class
3.   ?    The proportion of students who pass an exam
4.   ?    The suit of a playing card selected at random

If a discrete random variable, X, can take the values 1,2,5, and 10 with equal probability, what is the expected value of X?

1.   ?    4
2.   ?    4.5
3.   ?    5
4.   ?    3.5

4. If X has the probability distribution: x P(x)
1 0.2
2 0.4
3 0.4
Which of the following statements is true?

1.   ?    E(X) = 2.2, E(X²) = 4.84
2.   ?    E(X) = 2, E(X²) = 4
3.   ?    E(X) = 2.5, E(X²) = 5.2
4.   ?    E(X) = 2.2, E(X²) = 5.4

If X has the probability distribution in question 4.
What is the variance of X?.

1.   ?    0.56
2.   ?    3.2
3.   ?    1.78
4.   ?    0.2

If a random variable has mean 20 and standard deviation 2, which of the following can you say about the probability that it takes a value greater than 26?

1.   ?    At least 3/4
2.   ?    At most 1/9
3.   ?    Exactly 1/18
4.   ?    At most 1/3

In how many ways can 5 people form pairs to play a game of badminton doubles?

1.   ?    5
2.   ?    20
3.   ?    10
4.   ?    12

A coin is tossed 5 times and the number of heads observed. What is the probability of observing at least 2 heads?

1.   ?    0.1875
2.   ?    0.8125
3.   ?    0.3125
4.   ?    0.4

The average number of accidents at a particular road junction in a year is 2.5 and assumed to follow a Poisson distribution. What is the probability there are no road accidents at the junction in a given year?

1.   ?    0
2.   ?    1
3.   ?    0.205
4.   ?    0.082

Which of the following random variables have a Poisson probability distribution?

1.   ?    The number of drivers stopping at a roadside flower stand within an hour
2.   ?    The weight of a packet of crisps produced by a particular process
3.   ?    The number of the winning greyhound at a particular race track
4.   ?    The amount of rainfall recorded at a particular weather station