Practise

Question bank

Original exam-style questions, mapped to your syllabus. Answers are checked for mathematical equivalence and every attempt updates your mastery.

TopicSkillDifficulty

12 questions

SA-9709-P5-DV2-0012 marksL1 FoundationCalculatorE(X) and Var(X)

X

takes the values

1,2,3

with probabilities

0.5,\ 0.3,\ 0.2

. Find

E(X)

Salam Academy Original Practice · Proposed mark scheme

SA-9709-P5-DV2-0052 marksL1 FoundationCalculatorE(X) and Var(X)

A random variable has

E(X)=3

and

E(X^2)=13

. Find its standard deviation.

Salam Academy Original Practice · Proposed mark scheme

SA-9709-P5-DV2-0072 marksL1 FoundationCalculatorExpected value in context

Two fair coins are tossed and

X

is the number of heads. Find

E(X)

and

\text{Var}(X)

Salam Academy Original Practice · Proposed mark scheme

SA-9709-P5-DV2-0081 markL1 FoundationCalculatorE(X) and Var(X)

\text{Var}(X)=1.2

and

E(X)=2

. Find

E(X^2)

Salam Academy Original Practice · Proposed mark scheme

SA-9709-P5-DV-G014 marksL1 FoundationCalculatorE(X) and Var(X)

X

takes the values

1,2,3,4

with probabilities

0.1,0.3,0.4,0.2

respectively. Find

E(X)

and

\text{Var}(X)

Salam Academy Original Practice · Proposed mark scheme

SA-9709-P5-DV-Q021 markL1 FoundationCalculatorE(X) and Var(X)

\text{Var}(X)

equals

Salam Academy Original Practice · Proposed mark scheme

SA-9709-P5-DV2-0023 marksL2 StandardCalculatorE(X) and Var(X)

For the same

X

(values

1,2,3

with probabilities

0.5,\ 0.3,\ 0.2

E(X)=1.7

), find

\text{Var}(X)

Salam Academy Original Practice · Proposed mark scheme

SA-9709-P5-DV2-0032 marksL2 StandardCalculatorExpected value in context

A game costs

\$2

to play. A player wins

\$5

with probability

0.3

and nothing otherwise. Find the player's expected gain per game (negative for a loss).

Salam Academy Original Practice · Proposed mark scheme

SA-9709-P5-DV2-0043 marksL2 StandardCalculatorE(X) and Var(X)

X

takes the values

1,2,3,4

with probabilities

0.1,\ p,\ q,\ 0.3

, and

E(X)=2.8

. Find

p

and

q

Salam Academy Original Practice · Proposed mark scheme

SA-9709-P5-DV2-0063 marksL2 StandardCalculatorExpected value in context

X

is the score on a fair six-sided die. Find

E(X)

and

\text{Var}(X)

Salam Academy Original Practice · Proposed mark scheme

SA-9709-P5-DV2-0092 marksL2 StandardCalculatorExpected value in context

A raffle sells

200

tickets. There is one prize of

\$50

and two prizes of

\$20

. Find the expected value of the prize won by one ticket.

Salam Academy Original Practice · Proposed mark scheme

SA-9709-P5-DV-0124 marksL3 ExamCalculatorE(X) and Var(X)

X

takes the values

0,1,2,3

with probabilities

0.2,\ a,\ b,\ 0.1

. Given that

E(X)=1.4

, find

a

and

b

Salam Academy Original Practice · Proposed mark scheme