PSYC 2016 Exam 3

What is the F statistic used for in regression?

• To compare variances and determine if X predicts Y

• To calculate the mean difference between groups

• To measure correlation between variables

• To determine sample size requirements

Which of these is NOT a characteristic of the F distribution?

• Can contain negative values

• Always positively skewed

• Based on degrees of freedom

• Used for variance comparisons

What is the BIGGEST advantage of using related samples designs?

• Increases statistical power by reducing error variance

• Costs less money to conduct

• Takes less time to complete

• Requires fewer participants

Answer explanation

The biggest advantage of using related samples designs is that they increase statistical power by reducing error variance. This allows for more reliable results since individual differences are controlled for.

You calculate an F-obtained of 15.6 with F-critical of 10.13. What does this mean?

• Reject null hypothesis - relationship is significant

• Keep null hypothesis - no relationship

• Need more data to decide

• Test was done incorrectly

What does the standard error of estimate tell us in regression?

• Average distance of points from regression line

• Strength of the relationship between variables

• Variance of the residuals

• Slope of the regression line

Answer explanation

The standard error of estimate measures the average distance of points from the regression line, indicating how well the model predicts the dependent variable. Thus, the correct choice is the average distance of points from the regression line.

In an ANOVA test, what does a significant F statistic indicate?

• All group means are equal

• At least one group mean is different

• Variances are equal across groups

• Sample sizes are too small

Which of the following is a requirement for using the F test?

• Data must be nominal

• Data must be normally distributed

• Data must be ordinal

• Data must be binary

What is the purpose of using an F test in the context of multiple regression?

• To test the significance of individual predictors

• To test the overall significance of the model

• To test the correlation between predictors

• To test the homogeneity of variances

In the context of regression, what does a high F statistic suggest?

• The model is not a good fit

• The model explains a significant portion of the variance

• The predictors are not significant

• The sample size is too small

What is the relationship between the F statistic and the p-value in hypothesis testing?

• A high F statistic corresponds to a high p-value

• A high F statistic corresponds to a low p-value

• A low F statistic corresponds to a low p-value

• There is no relationship between F statistic and p-value