Exam 11: Correlation Coefficient and Simple Linear Regression Analysis

arrow
  • Select Tags
search iconSearch Question
flashcardsStudy Flashcards
  • Select Tags

A local grocery store wants to predict the daily sales in dollars. The manager believes that the amount of newspaper advertising significantly affects the store sales. The manager randomly selects 7 days of data consisting of daily grocery store sales (in thousands of dollars) and advertising expenditures (in thousands of dollars). The Excel/Mega-Stat output given below summarizes the results of fitting a simple linear regression model using this data. Regression Analysis 0.762 7 0.873 1 Std. Error 11.547 Dep. Var. Sales ANOVA table Source SS df MS F p -value Regression 2,133.3333 1 2,133.3333 16.00 .0103 Residual 666.6667 5 133.3333 Total 2,800.0000 6  Regression output \text { Regression output }\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad Confidence interval \text { Confidence interval } Variables Coefficients std. error t(df=5) p-value 95\% 95\% upper lower Intercep 63.3333 7.9682 7.948 .0005 42.8505 83.8162 Advertising 6.6667 1.6667 4.000 .0103 -Determine a 95% confidence interval estimate of the daily average store sales based on $3000 advertising expenditures? The distance value for this particular prediction is reported as .164.

Free
(Multiple Choice)
4.9/5
(31)
Correct Answer:
Verified

C

What is the explained variation?

Free
(Essay)
4.9/5
(36)
Correct Answer:
Verified

Explained variation = Total variation - Unexplained variation = 11.324 - 3.073 = 8.251

An experiment was performed on a certain metal to determine if the strength is a function of heating time.Results based on 10 metal sheets are given below.Use the simple linear regression model. X\sum X = 30 X2\sum X ^ { 2 } = 104 Y\sum Y = 40 Y2\sum Y ^ { 2 } = 178 XY\sum X Y = 134 -Calculate the correlation coefficient.

Free
(Essay)
4.8/5
(36)
Correct Answer:
Verified

.882 SSXY=134(30)(40)10=14SSYY=178(40)210=18SSXX=104(30)210=14r=14(18)(14)=.882\begin{array} { l } S S _ { X Y } = 134 - \frac { ( 30 ) ( 40 ) } { 10 } = 14 \\S S _ { Y Y } = 178 - \frac { ( 40 ) ^ { 2 } } { 10 } = 18 \\S S _ { X X } = 104 - \frac { ( 30 ) ^ { 2 } } { 10 } = 14 \\r = \frac { 14 } { \sqrt { ( 18 ) ( 14 ) } } = .882\end{array}

Calculate the t statistic and then using appropriate rejection point,test H0:

(Essay)
4.8/5
(31)

An experiment was performed on a certain metal to determine if the strength is a function of heating time.Results based on 10 metal sheets are given below.Use the simple linear regression model. X\sum X = 30 X2\sum X ^ { 2 } = 104 Y\sum Y = 40 Y2\sum Y ^ { 2 } = 178 XY\sum X Y = 134 -Determine the standard error.

(Essay)
5.0/5
(35)

A local grocery store wants to predict the daily sales in dollars. The manager believes that the amount of newspaper advertising significantly affects the store sales. The manager randomly selects 7 days of data consisting of daily grocery store sales (in thousands of dollars) and advertising expenditures (in thousands of dollars). The Excel/Mega-Stat output given below summarizes the results of fitting a simple linear regression model using this data. Regression Analysis 0.762 7 0.873 1 Std. Error 11.547 Dep. Var. Sales ANOVA table Source SS df MS F p -value Regression 2,133.3333 1 2,133.3333 16.00 .0103 Residual 666.6667 5 133.3333 Total 2,800.0000 6  Regression output \text { Regression output }\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad Confidence interval \text { Confidence interval } Variables Coefficients std. error t(df=5) p-value 95\% 95\% upper lower Intercep 63.3333 7.9682 7.948 .0005 42.8505 83.8162 Advertising 6.6667 1.6667 4.000 .0103 -What is the least-square prediction equation?

(Multiple Choice)
5.0/5
(32)

The sample ______________________ measures the strength and direction of the linear relationship between two quantitative variables.

(Short Answer)
5.0/5
(31)

The experimental region is the range of the previously observed values of the dependent variable.

(True/False)
4.9/5
(37)

Consider the following partial computer output from a simple linear regression analysis: Predictor Coef SE Coef Constant 5566.1 254.0 21.91 0.000 Independent Var -210.35 24.19 - S = _________ R-Sq = Analysis of Variance Source DF SS MS F P Regression 1 3963719 3963719 75.59 0.000 Residual Error 14 \_\_\_ 52439 Total 15 \_\_\_ -What is the estimated y-intercept?

(Essay)
4.7/5
(38)

A local tire dealer wants to predict the number of tires sold each month.The dealer believes that the number of tires sold is a linear function of the amount of money invested in advertising.The dealer randomly selects 6 months of data consisting of tire sales (in thousands of tires)and advertising expenditures (in thousands of dollars).Based on the data set with 6 observations,the simple linear regression equation of the least squares line is y^\hat { y } = 3 + 1x. X\sum X = 24 X2\sum X ^ { 2 } = 124 Y\sum Y = 42 Y2\sum Y ^ { 2 } = 338 XY\sum X Y = 196 MSE = 4 -Use the least squares regression equation and estimate the monthly tire sales when advertising expenditures is $4000

(Essay)
4.8/5
(46)

Determine the 95% confidence interval for the mean value of metal strength when the average heating time is 4 minutes.Provide an interpretation of this interval.

(Essay)
4.8/5
(33)

A data set with 7 observed pairs of data (x, y) yielded the following statistics. X\sum X =21.57 X2\sum X ^ { 2 } =68.31 Y\sum Y =188.9 Y2\sum Y ^ { 2 } =5140.23 XY\sum X Y =590.83 SSE = unexplained variation = 1.06 -You wish to perform a simple linear regression analysis using x as the independent variable and y as the dependent variable.What is the standard error?

(Multiple Choice)
4.9/5
(36)

Test to determine if there is a significant correlation between x and y Use H0: ρ = 0 versus Ha: ρ ≠ 0 by setting α = .01

(Essay)
4.8/5
(38)

The coefficient of determination is the proportion of total variation explained by the regression line.

(True/False)
4.9/5
(28)

In a simple linear regression analysis,if the correlation coefficient is positive,then:

(Multiple Choice)
4.7/5
(41)

A local grocery store wants to predict the daily sales in dollars. The manager believes that the amount of newspaper advertising significantly affects the store sales. The manager randomly selects 7 days of data consisting of daily grocery store sales (in thousands of dollars) and advertising expenditures (in thousands of dollars). The Excel/Mega-Stat output given below summarizes the results of fitting a simple linear regression model using this data. Regression Analysis 0.762 7 0.873 1 Std. Error 11.547 Dep. Var. Sales ANOVA table Source SS df MS F p -value Regression 2,133.3333 1 2,133.3333 16.00 .0103 Residual 666.6667 5 133.3333 Total 2,800.0000 6  Regression output \text { Regression output }\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad Confidence interval \text { Confidence interval } Variables Coefficients std. error t(df=5) p-value 95\% 95\% upper lower Intercep 63.3333 7.9682 7.948 .0005 42.8505 83.8162 Advertising 6.6667 1.6667 4.000 .0103 -What is the value of the coefficient of determination?

(Multiple Choice)
4.7/5
(37)

Consider the following partial computer output from a simple linear regression analysis. Predictor Coef SE Coef T P Constant 67.05 20.90 3.21 0.012 Independent Var 5.8167 0.7085 \_\_\_ 0.000 S = _________ R-Sq = _______ Analysis of Variance Source DF SS MS F P Regression 1 - 34920 67.39 0.000 Residual Error 8 - 518 Total 9 39065 -What is the estimated slope?

(Essay)
4.8/5
(32)

For simple linear regression model,the least-squares line is the equation that minimizes the sum of the squared deviations between each observed value of y and the line.

(True/False)
4.9/5
(35)

A local grocery store wants to predict the daily sales in dollars. The manager believes that the amount of newspaper advertising significantly affects the store sales. The manager randomly selects 7 days of data consisting of daily grocery store sales (in thousands of dollars) and advertising expenditures (in thousands of dollars). The Excel/Mega-Stat output given below summarizes the results of fitting a simple linear regression model using this data. Regression Analysis 0.762 7 0.873 1 Std. Error 11.547 Dep. Var. Sales ANOVA table Source SS df MS F p -value Regression 2,133.3333 1 2,133.3333 16.00 .0103 Residual 666.6667 5 133.3333 Total 2,800.0000 6  Regression output \text { Regression output }\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad Confidence interval \text { Confidence interval } Variables Coefficients std. error t(df=5) p-value 95\% 95\% upper lower Intercep 63.3333 7.9682 7.948 .0005 42.8505 83.8162 Advertising 6.6667 1.6667 4.000 .0103 -What are the limits of the 95% confidence interval for the population slope?

(Multiple Choice)
4.8/5
(34)

When using simple linear regression,we would like to use confidence intervals for the _____ and prediction intervals for the _____ at a given value of x.

(Multiple Choice)
4.9/5
(35)
Showing 1 - 20 of 190
close modal

Filters

  • Essay(0)
  • Multiple Choice(0)
  • Short Answer(0)
  • True False(0)
  • Matching(0)