Exam 26: Inferences for Regression

The index of exposure to radioactive waste and the cancer mortality rates (deaths per 100,000)were recorded for nine different geographic regions.Use the regression analysis and summary statistics provided below to determine a 95% confidence interval for the average cancer mortality rate of a county whose index of exposure is 6.81 Dependent variable is: Cancer Mortality Rate R-squared = 85.8% S = 14.00993 with 9 - 2 = 7 degrees of freedom

Applicants for a particular job,which involves extensive travel in Spanish-speaking countries,must take a proficiency test in Spanish.The sample data were obtained in a study of the relationship between the numbers of years applicants have studied Spanish and their score on the test.A 99% confidence interval for the slope of the regression line was determined to be (5.05,16.76).Give an interpretation of this interval. Dependent variable is: Score R-squared = 83.0% S = 5.65138 with 10 - 2 = 8 degrees of freedom

Applicants for a particular job,which involves extensive travel in Spanish-speaking countries,must take a proficiency test in Spanish.The sample data below were obtained in a study of the relationship between the numbers of years applicants have studied Spanish and their score on the test.A 95% confidence interval for the mean score of all applicants who have studied Spanish for 2.5 years was determined to be (53.0,64.6).Give an interpretation of this interval. Dependent variable is: Score R-squared = 83.0% S = 5.65138 with 10 - 2 = 8 degrees of freedom

A grass seed company conducts a study to determine the relationship between the density of seeds planted (in pounds per 500 sq ft)and the quality of the resulting lawn.Eight similar plots of land are selected and each is planted with a particular density of seed.One month later the quality of each lawn is rated on a scale of 0 to 100.The regression analysis is given below.Using a 10% level of significance,is there evidence of an association between seed density and lawn quality? Dependent variable is: Lawn Quality R-squared = 36.0% s = 9.073602 with 8 - 2 = 6 degrees of freedom

A grass seed company conducts a study to determine the relationship between the density of seeds planted (in pounds per 500 sq ft)and the quality of the resulting lawn.Eight similar plots of land are selected and each is planted with a particular density of seed.One month later the quality of each lawn is rated on a scale of 0 to 100.The regression analysis is given below.A 95% confidence interval for the slope of the regression line was determined to be (-1.51,10.58).Give an interpretation of this interval. Dependent variable is: Lawn Quality R-squared = 36.0% S = 9.073602 with 8 - 2 = 6 degrees of freedom

The index of exposure to radioactive waste and the cancer mortality rates (deaths per 100,000)were recorded for nine different geographic regions.Using a 1% level of significance,use the regression analysis provided below to perform the hypothesis test to determine if the index of exposure is useful as a predictor or cancer mortality rate. Dependent variable is: Cancer Mortality Rate R-squared = 85.8% s = 14.00993 with 9 - 2 = 7 degrees of freedom

Applicants for a particular job,which involves extensive travel in Spanish-speaking countries,must take a proficiency test in Spanish.The sample data were obtained in a study of the relationship between the numbers of years applicants have studied Spanish and their score on the test.Use the regression analysis and summary statistics given below to find a 95% prediction interval for the score of an applicant who has studied Spanish for 2.2 years. Dependent variable is: Score R-squared = 83.0% S = 5.65138 with 10 - 2 = 8 degrees of freedom

Ten students in a graduate program at the University of Toronto were randomly selected.Their grade point averages (GPAs)when they entered the program were between 3.5 and 4.0.The following data consist of the students' GPAs on entering the program and their current GPAs. Using a 10% level of significance,do the data below provide evidence of the conclusion that higher entering GPAs are associated with higher current GPAs?

Decide whether or not the conditions and assumptions for regression inference are satisfied. Explain your answer -

Determine which plot shows the strongest linear correlation.

The index of exposure to radioactive waste and the cancer mortality rates (deaths per 100,000)were recorded for nine different geographic regions.Use the regression analysis provided below to find a 99% confidence interval for the slope of the regression line. Dependent variable is: Cancer Mortality Rate R-squared = 85.8% S = 14.00993 with 9 - 2 = 7 degrees of freedom