Exam 12: Analysis of Variance

If the decision in the hypothesis test of the population correlation coefficient is to reject the null Hypothesis, what can we conclude about the correlation in the population?

The partial megastat output below is regression analysis of the relationship between annual payroll And number of wins in a season for 28 teams in professional sports. The purpose of the analysis is To predict the number of wins when given an annual payroll in $millions. Although technically not a Sample, the baseball data below will be treated as a convenience sample of all major league Professional sports. Refer to the printout above. The regression equation is:

Information was collected from employee records to determine whether there is an association Between an employee's age and the number or workdays they miss. Excel results are summarized Below: From this printout you determine:

i. The basic question in testing the significance of rho is to see if there is zero correlation in the Population from which the sample was selected. ii. An z test is used to test the significance of the coefficient of correlation. iii. Perfect correlation means that the scatter diagram will appear as a straight line.

The partial MegaStat output below is regression analysis of the relationship between annual payroll And number of wins in a season for 28 teams in professional sports. The purpose of the analysis is To predict the number of wins when given an annual payroll in $millions. Although technically not a Sample, the baseball data below will be treated as a convenience sample of all major league Professional sports. Refer to the printout above. Predict the number of wins for a team with a payroll of $36,000,000.

Information was collected from employee records to determine whether there is an association Between an employee's age and the number or workdays they miss. Excel results are summarized Below: From this printout you determine:

Which of the following is true about the standard error of estimate?

When comparing the 95% confidence and prediction intervals for a given regression analysis,

i. In order to visualize the form of the regression equation, we can draw a scatter diagram. ii. The least squares technique minimizes the sum of the squares of the vertical distances between The actual Y values and the predicted values of Y. iii. In regression analysis, the predicted value of Y' rarely agrees exactly with the actual Y value, i.e., We expect some prediction error.

i. A t test is used to test the significance of the coefficient of correlation. ii. When testing the strength of the relationship between two variables, the alternate hypothesis is: H0: ρ > 0. iii. Perfect correlation means that the scatter diagram will appear as a straight line

i. The coefficient of correlation is a measure of the strength of relationship between two variables. ii. The coefficient of determination can only be positive. iii. The standard error of estimate measures the accuracy of our prediction.

Given the following five points: (-2,0), (-1,0), (0,1), (1,1), and (2,3). What is the standard error of the estimate?

i. The technique used to measure the strength of the relationship between two sets of variables Using the coefficient of correlation and the coefficient of determination is called regression analysis. ii. In order to visualize the form of the regression equation, we can draw a scatter diagram. iii. The equation for a straight line going through the plots on a scatter diagram is called a Regression equation. It is alternately called an estimating equation and a predicting equation.

i. The technique used to measure the strength of the relationship between two sets of variables Using the coefficient of correlation and the coefficient of determination is called regression analysis. ii. In order to visualize the form of the regression equation, we can draw a scatter diagram. iii. When a regression line has a zero slope, indicating a lack of a relationship, the line is horizontal To the x-axis.

i. Perfect correlation means that the scatter diagram will appear as a straight line ii. If the coefficient of correlation is 0.80, the coefficient of determination is 0.64. iii. The coefficient of determination can assume values between 0% and 100%

What is the standard error of the estimate?

The following table shows the number of workdays absent based on the length of employment in Years. Determine the linear regression equation.

i. A correlation coefficient of -1 or +1 indicates perfect correlation. ii. A coefficient of correlation r close to 0 (say, 0.08) shows that the relationship between two Variables is quite weak. iii. Coefficients of -0.91 and +0.91 have equal strength.

Information was collected from employee records to determine whether there is an association Between an employee's age and the number or workdays they miss. Partial excel results are Summarized below: Given this information alone, would you decide to continue with the regression analysis?

A sales manager for an advertising agency believes there is a relationship between the number of Contacts and the amount of the sales. To verify this believe, the following data was collected: What is the independent variable?