IPP BIOSTAT DR. AUSTIN PPX2 and PPX3

Which of the following would be removed if variable Z can be incorporated into regression

• bias/inefficiency associated with Z

• bias/inefficiency associated with t

Which of the following are TRUE about variable Z?

• control variables

• If variable Z can be incorporated into regression, bias/inefficiency associated with Z IS NOT going to be removed.

What equation is this?

• Multiple Regression

• Single Regression

What ε represents in this equation?

• coefficient estimate

• residual

• indexes of each of the n observations

• estimate of slope

• estimate of intercept

What b2 represents in this equation?

• estimate the slope

• coefficient estimate

• estimate of intercept

• the residual

Will ε be larger or smaller than u?

• u has to be bigger than E

• they have to be the same value

With two regressors (X and Z) trendline becomes?

• a plane

• a line

Which of the following is Z considered besides being a control variable?

• effect mediator

• effect modificatory

• confounder

• omitted variable

Which of the following reflects marginal impact of X change on Y while controlling for Z on multiple regression?

• b0

• b1

• i

• Z

b1 reflects marginal impact of X change on Y only?

• simple regression

• multiple regression