Final answer:
The independent variable in regression analysis is the cost driver used to estimate the value of the dependent variable, and it is the variable presumed to influence the outcome.
Step-by-step explanation:
The independent variable in regression analysis is b) the cost driver used to estimate the value of the dependent variable. In regression analysis, the independent variable, also known as the predictor or explanatory variable, is the variable that is presumed to cause, influence, or predict the outcome. It is the variable that the researcher manipulates or categorizes to determine if it has an effect on the dependent variable, which is the variable of interest that is being measured or predicted.
For instance, in determining whether the weekly grocery bill changes based on the number of family members (situation b), the number of family members would be the independent variable since it's presumed to influence the grocery bill, the dependent variable. Similarly, age would be the independent variable when estimating insurance premiums (situation c), as it is used to predict the dependent variable, the cost of premiums.