According to a survey of 1000 households randomly selected by the Bureau of Labor Statistics, 87% of rural households own their own homes. Which of the following is closest to a 95% confidence interval fo the proportion of all rural households that own their own homes? Select one: O a. (0.859, 0.881) O b. (0.853, 0.887) O c. (0.849, 0.891) O d. (0.838, 0.902) Student researchers investigated whether balsa wood is less elastic after it has been immersed in water. They took 60 pieces of balsa wood and randomly assigned half to be immersed in water and the other half not to be. They measured the elasticity by seeing how far (in inches) the piece of wood would project a dime into the air. Below are the summary statistics for the study: n mean sd Treated (in water) 30 7.63 2.33 Untreated (no water) 30 11.78 2.67 What is the 95% confidence interval for the difference in mean elasticity between treated and untreated balsa wood (use untreated as group 1 and treated as group 2)? Select one: O a. (-8.53, -4.29) O b. (0.15, 2.35) O c. (2.85, 5.45) O d. (-3.53, 2.27) age