The mean of a discrete random variable is the mean of its:

second and third quartiles

probability distribution

percentage distribution

frequency distribution

A continuous random variable x has a right-skewed distribution with a mean of 80 and a standard deviation of 12. The sampling distribution of the sample mean for a sample of 50 elements taken from this population is:

skewed to the right

skewed to the left

approximately normal

not normal

The regression model y = A + Bx + e is:

a nonlinear model

an exact relationship

a probabilistic model

a deterministic model

The model y = A + Bx is a:

deterministic model

nonlinear model

stochastic model

probabilistic model

In a hypothesis test, a Type II error occurs when:

a false null hypothesis is rejected

a false null hypothesis is not rejected

a true null hypothesis is rejected

a true null hypothesis is not rejected