Please help verify answers

Questions 11 - 12 (3 points each): Use the following scenario to answer the questions. Consider the residual plots below. What do they tell you about the relationship of the variables in a simple linear regression analysis? Each residual plot matches a specific violation or no violations. Plot A Plot B 100 200 300 50 150 Explanatory Explanatory Plot C Plot D 2 110 Explanatory 11. Which plot provides evidence the variance is not the same for all values of the explanatory variable? A. Plot A B. Plot B C. Plot C D. Plot D Answer: 12. Which plot provides evidence the relationship between the response and predictors is not linear? A. Plot A B. Plot B C. Plot C D. Plot D Answer: 5Questions 13 - 15 (3 points each): Answer the following questions. 13. The 90% confidence interval for / is (1.8, 3.2). Assuming n = 13 and that o is unknown, what is the 95% confidence interval? A. (1.646, 3.384) B. (1.644, 3.356) C. (1.926, 3.074) D. (1.928, 3.072) Answer: 14. Fill in the blank cells (indicated with a "?") of the ANOVA table below (Each correct answer is worth 3 points): Degrees of Source Freedom Sum of Squares Mean Squares Treatments 5 ? ? 7.8 Error 7640.0 95.5 Total 85 ? 15. In a hypothesis test, if we fail to reject a true null hypothesis, we make... A. the correct choice. B. a type I error. C. a type II error. D. All of the above Answer: Questions 16 - 20: Use the following scenario to answer the questions. A rocket motor is manufactured by bonding together two types of propellants, an igniter and a sustainer. A random sample of 20 specimens is used to investigate the relationship between the shear strength of the bond (in psi) and the age of the propellant (in weeks). Use the R software output to answer the following questions. Rocket Motors Coefficients: 2500 Estimate Std. Error t-value Pr(>|t|) (Intercept) 2641. 185 68 .901 38.33 Direction: Form: Outliers: 17. (4 points) Write down the least squares regression equation. D =18. (4 points) Calculate the residual for the observation that is 12.4 weeks old with bond strength of 1993.8 psi. Write your answer in the blank and show your work. 19. (4 points) Based on the residual plot in part below, state all of the conditions for the least squared regression model to be valid, whether or not they are satisfied, and why. Residuals 100 Residuals 100 200 -300 10 15 20 26 Propellant Age (in Weeks) 20. (4 points) Interpret the estimated slope of the linear model: