Research II study guide

In the regression equation, a = ______. A) Y-intercept B) slope C) regression coefficient D) correlation

A) Y-intercept

Correlational designs can have greater external validity than experiments because correlational designs ______. A) better represent the everyday world where we do not manipulate or control events B) study true relationships while experiments only manipulate relationships C) are more attractive to participants D) easier to conduct

A) better represent the everyday world where we do not manipulate or control events

A regression equation allows you to ______. A) more closely estimate the value of Y for a given Xvalue B) make predictions of Y that match the actual values of y C) predict only the whole number values D) eliminate any error in the prediction of Y values

A) more closely estimate the value of Y for a given Xvalue

One reason to use a correlational design is ______. A) when an experimental study would be unethical B) when it is possible to manipulate the variable(s) of interest C) to examine causality D) to increase internal validity

A) when an experimental study would be unethical

In the regression equation, b = ______. A)slope B)Y-intercept C)correlation D)ordinal variable

A)slope

The strength of the relationship is evident from ______ and the direction of the relationship is evident from ______ in a correlation coefficient. A) how close the correlation coefficient is to +1.0; the sign of the coefficient B) how close the correlation coefficient is to the absolute value of 1.0; the sign of the coefficient C) whether the correlation coefficient is positive or negative; the scatterplot D) the scatterplot; the combination of the variables' predicted values

B) how close the correlation coefficient is to the absolute value of 1.0; the sign of the coefficient

Anne and Jack are examining variables related to self-control. Anne finds r = +.40 between percentage of salary saved and self-control while Jack finds r = -.60 between impulsivity and self-control. Which variable is more strongly related to self-control? A) percentage of salary saved B) impulsivity C) neither variable is significantly related to self-control D) you cannot tell from the information provided

B) impulsivity

A correlational design ______. A) describes the relationship between two variables B) is a type of study that tests the hypothesis that variables are related C) determines causation between variables D) examines causal relationships between three or more variables

B) is a type of study that tests the hypothesis that variables are related

When two variables move in opposite directions (one increases while the other decreases), they are ______. A) positively correlated B) negatively correlated C) not correlated D)perfectly correlated

B) negatively correlated

The value of Pearson's r ranges between ______. A) 0.0 and +1.0 B) -1.0 and 0.0 C) -1.0 and +1.0 D) 0.0 and 10.0

C) -1.0 and +1.0

Shawn examines the relationship between creativity and academic honesty and finds the coefficient of determination equals .33 or r2= -.33. This means that ______. A) he has found a moderate correlation between the two variables B) he has found a strong correlation between the two variables C) 33% of the variability in academic honesty is accounted for by knowing its relationship with creativity D) 67% of the variability in academic honesty is accounted for by knowing its relationship with creativity

C) 33% of the variability in academic honesty is accounted for by knowing its relationship with creativity

The statistic used to determine whether a linear relationship exists between two interval/ratio variables is the ______. A) Cohen's d B) Y¢determined by a regression equation C) Pearson's r D) multiple r

C) Pearson's r

The line of best fit represents ______. A) predictions of all the nominal variable values B) the best values for the measures C) the predicted Y values (Y¢) for each X value in the sample range D) the actual X and Y values for your sample

C) the predicted Y values (Y¢) for each X value in the sample range

Correlation is the statistic used to assess ______. A) causation between two interval/ratio variables B) relationships between two ordinal/ratio variables C) the validity and reliability of measures D) the lack of significant results

C) the validity and reliability of measures

We should not compute a regression equation if we do not find a significant correlation between two variables because ______. A) we need to correct errors in our data B) we can only compute regression equations when variables are causally related C) there will be too much error in our predicted values D) the slope of the regression equation would be flat

C) there will be too much error in our predicted values

The average error between predicted Y values and the actual Y values is called ______. A)line of best fit B)standard error of the correlation C)standard error of the estimate D)estimated standard error of the estimate

C)standard error of the estimate

The statistic that describes the proportion of variability that is accounted for by knowing the relationship between two variables is the ______. A) coefficient of prediction B) standard error of the estimate C) estimated standard error of the means D) coefficient of determination

D) coefficient of determination

The regression equation is always represented by the formula ______. A) X¢ = Yb + X B) X¢ = bX + Y C) Y¢ = a - bX D) Y¢ = bX + a

D) Y¢ = bX + a

The regression equation includes the slope and Y-intercept values which allow one to graph the line. A) True B) False

True