Exam 14: Correlation and Regression

The line defined by the Y = -3X + 6 slopes up to the right.

A researcher obtains SS_X = 20,SS_Y = 5,and SP = 7 for a set of n = 25 pairs of scores.The Pearson correlation for these scores is r = 7/10 = 0.70.

For a group of graduating college seniors,a researcher records each student's rank in his/her high school graduating class and the student's rank in the college graduating class.Which correlation should be used to measure the relationship between these two variables?

If there is a positive correlation between X and Y,then the regression equation Y = bX + a will have _____.

If people are classified by age (over 30/under 30)and by political affiliation (Democrat/Republican),then the point-biserial correlation would be the proper technique to measure the relationship between the two variables.

For linear regression calculated for a sample of n = 20 pairs of X and Y values,what is the value for degrees of freedom for the predicted portion of the Y-score variance,MS_regression?

Which of the following Pearson correlations shows the greatest strength or consistency of relationship?

A set of n = 10 pairs of scores has ΣX = 20,ΣY = 30,and ΣXY = 74.What is the value of SP for these data?

The following X and Y scores produce SS_X = 2 and SP = 8.What is regression equation for predicting Y?

Suppose the correlation between height and weight for adults is +0.40.What proportion (or percent)of the variability in weight can be explained by the relationship with height?

The value obtained for the sum of products,SP,determines the sign (+/)for the Pearson correlation.

A negative correlation means that decreases in the X variable tend to be accompanied by decreases in the Y variable.

As the sample size gets larger,what happens to the size of the correlation that is needed for significance?

What is indicated by a positive value for a correlation?

For the regression equation,Ŷ = -2X + 6 if the X value is above the mean (positive deviation),what can be determined about the predicted Y value?

If the Spearman correlation for a set of scores is equal to +1.00,then the Pearson correlation for the same scores would also be equal to +1.00.

A Pearson correlation of r = 0.90 indicates that the data points are clustered close to a line that slopes down to the right.

For linear regression,the value of SS_residual can be computed directly by Σ(Y - ?4Y)².

A researcher measures IQ and weight for a group of college students.What kind of correlation is likely to be obtained for these two variables?

For a regression equation with a positive slope,if the X value is above the mean for the X scores,then the predicted Y value will be above the mean for the Y scores.