Questions
1. The probabilities of an event are:
P
(
A
)=0.35
Find
P
(
A'
)
.
2. A fair die is rolled twice. Find the probability of two sixes.
3. The mean of five numbers is 12. Find their total.
4. Calculate the standard deviation of:
2
,
4
,
6
5. A bag contains 4 red, 5 blue and 3 green balls. Find:
P
(green )
6. Find:
P
(
A ∪ B
)
if
P
(
A
)=0.6
,P
(
B
)=0.5
,P
(
A ∩ B
)=0.2
7. A discrete random variable has:
x 1 2 4
P(X=
x)
0.
2
0.
5
0.
3
Find
E
(
X
)
.
8. State one limitation of using the mean.
9. Find the median of:
5
,
7
,
8
,
10
,
12
,
14
,
16
10. A survey of 120 students found 72 liked maths. Estimate the
probability that a randomly selected student likes maths.
Answers
