Exam 13: Chi-Square Tests

A local tire dealer wants to predict the number of tires sold each month.He believes that the number of tires sold is a linear function of the amount of money invested in advertising.He 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 model yielded the following results. Find the estimated slope.

A local tire dealer wants to predict the number of tires sold each month.He believes that the number of tires sold is a linear function of the amount of money invested in advertising.He 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 ŷ = 3 + 1x. MSE = 4 Using the sums of the squares given above,determine the 90 percent confidence interval for the mean value of monthly tire sales when the advertising expenditure is $5,000.

In simple linear regression analysis,we assume that the variance of the independent variable (X)is equal to the variance of the dependent variable (Y).

An experiment was performed on a certain metal to determine if the strength is a function of heating time.The 95 percent confidence interval for the average strength of a metal sheet when the average heating time is 4 minutes is from 4.325 to 5.675.Therefore,we are confident at α = .05 that the average strength of this metal heated for four minutes is between 4.325 and 5.675 pounds per square inch.Do you agree or disagree with this statement?

A local tire dealer wants to predict the number of tires sold each month.He believes that the number of tires sold is a linear function of the amount of money invested in advertising.He 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 model yielded the following results. Calculate the sample correlation coefficient.

A simple regression analysis with 20 observations would yield ________ degrees of freedom error and _________degrees of freedom total.

If the Durbin-Watson statistic is less than d_L,then we conclude that

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. Calculate the coefficient of determination.

When the constant variance assumption holds,a plot of the residual versus x

Regression Analysis A local grocery store wants to predict its daily sales in dollars.The manager believes that the amount of newspaper advertising significantly affects sales.He 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/MegaStat output given above summarizes the results of the regression model.What is the value of the simple coefficient of determination?

Based on 30 time-ordered observations from a simple regression,we have determined the Durbin-Watson statistic,d = 2.71.At α = .05,test to determine if there is any evidence of negative autocorrelation.State your conclusions.

A data set with 7 observations yielded the following.Use the simple linear regression model. Determine the 95 percent confidence interval for the average value of Y when x = 3.25.

An experiment was performed on a certain metal to determine if the strength is a function of heating time.Partial results based on a sample of 10 metal sheets are given below.The simple linear regression equation is = 1 + 1X.The time is in minutes,the strength is measured in pounds per square inch,MSE = 0.5, = 30,and = 104.Determine the 95 percent confidence interval for the mean value of metal strength when the average heating time is 4 minutes.

A local tire dealer wants to predict the number of tires sold each month.He believes that the number of tires sold is a linear function of the amount of money invested in advertising.He 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 model yielded the following results. Calculate the coefficient of determination.

A data set with 7 observations yielded the following.Use the simple linear regression model. Find the estimated slope.

The point estimate of the variance in a regression model is