STAT 3331 EXAM 2 (CHAPTER 7)

A variable used to model the effect of categorical independent variables in a regression model is known as a _____

dummy variable

The degree of correlation among independent variables in a regression model is called _____.

multicollinearity

Fitting a model too closely to sample data, resulting in a model that does not accurately reflect the population is termed as _____.

overfitting

A normally distributed error term with a mean of zero would _____.

allow more accurate modeling

In a linear regression model, the variable (or variables) used for predicting or explaining values of the response variable are known as the _____. It(they) is(are) denoted by x.

independent variable

A _____ is used to visualize sample data graphically and to draw preliminary conclusions about the possible relationship between the variables.

scatter chart

In the graph of the simple linear regression equation, the parameter ß1 is the _____ of the true regression line.

slope

The graph of the simple linear regression equation is a(n) _____.

straight line

_____ is used to test the hypothesis that the values of the regression parameters ß1, ß2, ... ßq are all zero.

An F test

r^2 (coefficient of determination)

SSR/SST

_____ refers to the scenario in which the relationship between the dependent variable and one independent variable is different at different values of a second independent variable.

Interaction

_____ refers to the use of sample data to calculate a range of values that is believed to include the value of the population parameter.

Interval estimation

_____ refers to the degree of correlation among independent variables in a regression model

Multicollinearity

_____ refers to the data set used to compare model forecasts and ultimately pick a model for predicting values of the dependent variable.

Validation set

A variable used to model the effect of categorical independent variables in a regression model which generally takes only the value zero or one is called _____.

a dummy variable

The population parameters that describe the y-intercept and slope of the line relating y and x, respectively, are _____.

b. B0 and B1

The _____ is a measure of the goodness of fit of the estimated regression equation. It can be interpreted as the proportion of the variability in the dependent variable y that is explained by the estimated regression equation.

coefficient of determination

The _____ is the range of values of the independent variables in the data used to estimate the regression model.

experimental region

Prediction of the mean value of the dependent variable y for values of the independent variables x1, x2, . . . , xq that are outside the experimental range is called _____.

extrapolation

Prediction of the value of the dependent variable outside the experimental region is called _____.

extrapolation

The process of making a conjecture about the value of a population parameter, collecting sample data that can be used to assess this conjecture, measuring the strength of the evidence against the conjecture that is provided by the sample, and using these results to draw a conclusion about the conjecture is known as _____.

hypothesis testing

_____ is a statistical procedure used to develop an equation showing how two variables are related.

regression analysis

In the graph of the simple linear regression equation, the parameter ß0 represents the _____ of the true regression line.

y intercept (sometimes)