Which of the following is a difference between least absolute deviations (LAD) and ordinary least squares (OLS) estimation?

a. OLS is more computationally intensive than LAD.

b. OLS is more sensitive to outlying observations than LAD.

c. OLS is justified for very large sample sizes while LAD is justified for smaller sample sizes.

d. OLS is designed to estimate the conditional median of the dependent variable while LAD is designed to estimate the conditional mean.

Which of the following correctly identifies a difference between cross-sectional data and time series data?

a. Cross-sectional data is based on temporal ordering, whereas time series data is not.

b. Time series data is based on temporal ordering, whereas cross-sectional data is not.

c. Cross-sectional data consists of only qualitative variables, whereas time series data consists of only quantitative variables.

d. Time series data consists of only qualitative variables, whereas cross-sectional data does not include qualitative variables.

A stochastic process refers to a:

a. sequence of random variables indexed by time.

b. sequence of variables that can take fixed qualitative values.

c. sequence of random variables that can take binary values only.

d. sequence of random variables estimated at the same point of time.