Topic 3

Question 1

Sampling

Answer 1

Randomly selecting items from a set or population

Question 2

Random Variable

Answer 2

A numeric quantity whose value depends on the outcome of a random event

Question 3

Discrete Random Variable

Answer 3

Only takes numeric values (dice roll)

Question 4

Continuous Numeric Variables

Answer 4

Can take decimal values (height)

Question 5

Expected Value

Answer 5

Weighted average of the possible outcomes

Question 6

Variance

Answer 6

𝜎^2 = 𝑉𝑎𝑟 𝑋 = k ∑ 𝑖=1 (𝑥𝑖−𝐸(𝑋))^2P(𝑋 = 𝑥𝑖 ) where xi is the difference between the actual and expected outcome

Question 7

Standard Deviation

Answer 7

𝜎 = SD(X) = √𝑉𝑎𝑟 𝑋

Question 8

Linear Combination (of Random Variables)

Answer 8

aX + bY where a, b fixed numbers

Question 9

Expected Value of a Linear Combination

Answer 9

E(aX + bY) = a x E(X) + b x E(Y)

Question 10

Variability of a Linear Combination of two Independent Random Variables

Answer 10

Var(aX + bY) = a^2 x Var(X) + b^2 x Var(y)

Question 11

Finding Continuous Probabilities From a Graph

Answer 11

Area under the curve- ∫ b,a f(x)dx