MNS 601-A polling company wants to be very careful

1. A polling company wants to be very careful in its upcoming opinion survey on an upcoming tax proposition. To ensure precision, it is willing to sample as many respondents as is necessary. In a small pilot survey of 100 residents, it found that only 17 of them said they intended to vote "yes" on the proposition. How large does the sample sizeneed to be in the full survey to achieve 2 percent margin of error with 99 percent confidence?

2. The following data represent crop yields in bushels per acre versus quantity of fertilizer applied in pounds per acre:

Fertilizer applied Yield

235 3350

330 3540

355 3450

420 4200

445 4300

465 4420

480 4460

500 4470

(a) Graph the scatter diagram. Is a linear regression model appropriate? (5)

(b) Compute the regression coefficients "b₀" and "b₁", state the regression equation, and graph the regression line on the scatter diagram. (10)

(c) If 475 pounds per acre were applied, what would you predict the yield in bushels per acre to be? (5)

(d) Compute the coefficient of determination and correlation coefficient of the regression. What does it tell you about the accuracy of your answer in part (b)? (5)