What is adjusted R-square? | a conservative version of R-square that is always less than regular R-square |

What is control by adjustment? | a form of statistical control in which a mathematical adjustment is made to assess the impact of a third variable |

What is control by grouping? | a form of statistical control in which observations identical or similar to the control variable are grouped together |

What is correlation analysis? | produces a measure of association, known as Pearson's correlation coefficient or Pearson's , that measures the direction and magnitude of a relationship between two INTERVAL-LEVEL variables |

What is a dummy variable? | a hypothetical index that has just two values: 0 for the presence (or absence) of a factor and 1 for its absence (or presence) |

What is an efficient estimator? | An estimator having standard error smaller than those of other estimators is said to be efficient. An efficient estimator falls closer, on average, than other estimators to the parameter. |

What is the error sum of squares? | the prediction error, the part of the total sum of squares that is not accounted for by the regression equation |

What is an estimator? | the particular type of statistic for estimating a parameter |

What is experimental control? | manipulation of the exposure of experimental groups to experimental stimuli to assess the impact of a third variable |

What is explication? | the specification of the conditions under which X and Y are and are not related |

What is an interaction effect? | An interaction effect occurs when the effect of an independent variable cannot be fairly summarized by a single partial effect. Instead, the effect varies, depending on the value of another independent variable in the model. |

What is an interaction variable? | The multiplicative product of two (or more) independent variables. |

What is an interval estimate? | An interval of numbers around a point estimate, within which the parameter is believed to fall |

What is a linear probability model? | regression model in which a dichotomous variable is treated as the dependent variable |

What is multicollinearity? | Multicollinearity occurs when the independent variables are related to each other so strongly that it becomes difficult to estimate the partial effect of each independent variable on the dependent variable. |

What is a multiple correlation coefficient? | a statistic varying between 0 and 1 that indicates the proportion of the total variation in Y, a dependent variable, that is statistically explained by the independent variables |

What is multiple regression? | In multiple regression, we are able to isolate the effect of one independent variable on the dependent variable, while controlling for the effects of the other independent variable(s). |

What is multiple regression analysis? | a technique for measuring the mathematical relationships between more than one independent variable and a dependent variable while controlling for all other independent variables in the equation |

What is a multiple regression coefficient? | a number that tells how much Y will change for a one-unit change in a particular independent variable, if all the other variables in the model have been held constant |

What is multivariate analysis? | data analysis techniques designed to test hypotheses involving more than two variables |

What is multivariate cross-tabulation? | a procedure by which cross-tabulation is used to control for a third variable |

What is a partial regression coefficient? | a number that indicates how much a dependent variable would change if an independent variable changed one unit and all other variables in the equation or model were held constant |

What is a partly spurious relationship? | a relationship between two variables caused partially by a third |

What is Pearson's correlation coefficient? | a measure of association which always has a value between -1 and 1; -1 showing perfectly negative association between variables and 1 showing perfectly positive association between variables |

What is a point estimate? | A single number that is the best guess for a parameter |

What is prediction error? | The difference between the value of the dependent variable estimated from a regression equation and its actual value. |

What is regression analysis? | a technique for measuring the relationship between two interval- or ratio-level variables |

What is a regression coefficient? | a statistic that indicates the strength and direction of the relationship between two quantitative variables |

What is a regression constant? | value of the dependent variable when all the values of the independent variables in the equation equal zero |

What is a regression line? | An algebra-type equation that specifies the relationship among variables on interest. |

What is the regression sum of squares? | the component of the total sum of squares that we pick up by knowing the independent variable |

What is R-square? | a statistic, sometimes called the coefficient of determination, defined as the explained sum of squares divided by the total sum of squares. It purportedly measures the strength of the relationship between a dependent variable and one or more independent variables |

What is a scatterplot? | a plot of Y-X values on a graph consisting of an x-axis drawn perpendicular to a y-axis. The axes represent the values of the variables. Usually the x-axis represents the independent variable if there is one and is drawn horizontally; the y-axis is vertical. Observed pairs of Y-X values are plotted on this coordinate system |

What is a specified relationship? | a relationship between two variables that varies with the values of a third |

What is statistical control? | assessing the impact of a third variable by comparing observations across the values of a control variable |

What is the total sum of squares? | an overall summary of the variation in the dependent variable |

What is an unbiased estimator? | An estimator is unbiased if its sampling distribution centers around the parameter; the parameter is the mean of the sampling distribution. By contrast, a biased estimator tends to underestimate or overestimate the parameter. |

What are the assumptions about residuals? | Assumptions about “random noise” in regression analysis, qualities that “random noise” must have in order to truly be noise. |

What is listwise deletion? | In multiple regression analysis, if an observation is missing values on any variable, that observation is omitted and the regression only proceeds with complete observations. |

What is ordinary least squares? | The criteria used to estimate regression coefficients; regression coefficients are found to minimize the sum of the squared differences between the observed values of y and estimated values of y. |

Define parsimony. | Concept that should guide the inclusion of more independent variables in multiple regression analysis – one should consider being stingy with including more variables. |