AP Stats AP Stats Random Variables and Expected Value 2

Question 1

A binomial setting requires which of the following conditions?

Accepted Answer

Fixed number of trials, two outcomes, constant probability, independent trials

Answer

Observations are dependent and outcomes are continuous

Answer

At least 30 trials and normal distribution of outcomes

Answer

Sampling without replacement from a large population only

Question 2

For X ~ Binomial(n = 10, p = 0.3), what is P(X = 3)?

Accepted Answer

C(10,3)(0.3)³(0.7)⁷

Answer

C(10,3)(0.3)⁷(0.7)³

Answer

(0.3)³(0.7)⁷

Answer

C(10,3)(0.3)³

Question 3

The standard deviation of a binomial random variable X ~ Binomial(n, p) is:

Accepted Answer

√[np(1−p)]

Answer

np

Answer

np(1−p)

Answer

√(np)

Question 4

Which condition is required to use a geometric distribution?

Accepted Answer

Trials continue until the first success

Answer

A fixed number of trials is set in advance

Answer

All outcomes have equal probability

Answer

The variable is continuous

Question 5

If X and Y are independent random variables, what is Var(X − Y)?

Accepted Answer

Var(X) + Var(Y)

Answer

Var(X) − Var(Y)

Answer

|Var(X) − Var(Y)|

Answer

Var(X) × Var(Y)

Question 6

A random variable X has μ = 5 and σ = 2. If Y = 3X − 4, what is σ_Y?

Accepted Answer

6

Answer

2

Answer

10

Answer

4