IEE 380 Prob and Stats Chapter 3
Question and answers 100% correct
2025/2026
Probability Distribution - correct answer ✔For a sample space, a description of the set of possible
outcomes along with a method to determine probabilities. For a random variable, a probability
distribution is a description of the range along with a method to determine probabilities
Probability Mass Function - correct answer ✔A function that provides probabilities for the values in the
range of a discrete random variable.
1) f(xi) >= 0
2) Sum f(xi) = 1
3) f(xi) = P(X = xi)
Cumulative Distribution Function - correct answer ✔For a random variable X, the function of X defined
as P(X <= x) that is used to specify the probability distribution.
1) F(x) = P(X<=x) = SUM f(xi)
2) 0<=F(x) <=1
3) If x<=y, then F(x) <= F(y)
Mean - correct answer ✔Expected value of a random variable
Mu = E(X) = Sum x*f(x)
Variance - correct answer ✔A measure of variability defined as the expected value of the square of the
random variable around its mean.
Sigma^2 = V(X)
=E(X - Mu)^2
Question and answers 100% correct
2025/2026
Probability Distribution - correct answer ✔For a sample space, a description of the set of possible
outcomes along with a method to determine probabilities. For a random variable, a probability
distribution is a description of the range along with a method to determine probabilities
Probability Mass Function - correct answer ✔A function that provides probabilities for the values in the
range of a discrete random variable.
1) f(xi) >= 0
2) Sum f(xi) = 1
3) f(xi) = P(X = xi)
Cumulative Distribution Function - correct answer ✔For a random variable X, the function of X defined
as P(X <= x) that is used to specify the probability distribution.
1) F(x) = P(X<=x) = SUM f(xi)
2) 0<=F(x) <=1
3) If x<=y, then F(x) <= F(y)
Mean - correct answer ✔Expected value of a random variable
Mu = E(X) = Sum x*f(x)
Variance - correct answer ✔A measure of variability defined as the expected value of the square of the
random variable around its mean.
Sigma^2 = V(X)
=E(X - Mu)^2
