Exam 8: Trendlines and Regression Analysis

The following table exhibits the age of antique furniture and the corresponding prices. Use the table to answer the following questions). Hint: Use scatter diagram and the Excel Trendline tool where necessary). Number of years Value \ 79 930 91 1010 83 970 159 1950 134 1610 210 2880 89 980 178 2010 124 1370 72 900 -What is the relationship between the age of the furniture and their values?

means that the variation about the regression line is constant for all values of the independent variable.

When using the t-statistic in multiple regression to determine if a variable should be removed:

A good regression model has the fewest number of explanatory variables providing an adequate interpretation of the dependent variable.

Explain the concept of curvilinear regression model.

An increase in adjusted ^R2 indicates that the regression model has improved.

The best-fitting line maximizes the residuals.

Use the data given below to answer the following questions). Following is an extract from the database of a construction company. The table shows the height of walls in feet and the cost of raising them. The estimated simple linear regression equation is given as Ŷ = b0 + b1X. Hint: Use Excel functions). $\begin{array} { | r | r | } \hline \text { Height ft) } & \text { Cost \$) } \\\hline 4 & 670 \\\hline 3 & 430 \\\hline 7 & 810 \\\hline 9 & 1100 \\\hline 6 & 790 \\\hline 8 & 880 \\\hline 5 & 760 \\\hline 11 & 1200 \\\hline\end{array}$ -Which of the following statements is true when using the Excel Regression tool?

Use the data given below to answer the following questions). Following is an extract from a firm's database detailing the number of hours spent on the job by employees and their corresponding pay. Note: Assume a level of significance of 0.05 wherever necessary.) Hours spent on the job Salary \ 4 340 12 850 7 570 5 470 11 820 8 610 9 630 13 900 10 800 6 480 -Is the hours spent on the job a statistically significant variable in explaining the variation in pay of employees? Hint: Use Regression tool).

Which of the following is true when testing for normality of errors?

For a simple linear regression model, significance of regression is:

Use the data given below to answer the following questions). Following is an extract from the database of a construction company. The table shows the height of walls in feet and the cost of raising them. The estimated simple linear regression equation is given as Ŷ = b0 + b1X. Hint: Use Excel functions). $\begin{array} { | r | r | } \hline \text { Height ft) } & \text { Cost \$) } \\\hline 4 & 670 \\\hline 3 & 430 \\\hline 7 & 810 \\\hline 9 & 1100 \\\hline 6 & 790 \\\hline 8 & 880 \\\hline 5 & 760 \\\hline 11 & 1200 \\\hline\end{array}$ -What is the estimated cost of raising a 10-inch wall?

When two or more independent variables in the same regression model can predict each other better than the dependent variable, the condition is referred to as .

Excel's Trendline feature cannot be used in modeling trends which include time variables.

The R² value:

In a quadratic regression model, the represents the curvilinear effect.

A regression model that involves a single independent variable is called .

Interaction is: