1. I want to know which of two manufacturing methods will be better. I create 10 prototypes using the first process, and 10 using the second. There were 3 defectives in the first batch and 5 in the second. Find a 95% confidence interval for the difference in the proportion of defectives.
A. (-0.62, 0.22)
B. (-0.56, 0.22)
C. (-0.493, 0.160)
2. I want to know which of two manufacturing methods will be better. I create 10 prototypes using the first process, and 10 using the second. There were 3 defectives in the first batch and 5 in the second. The 90% confidence interval for the difference in the two proportions is (-0.493, 0.159). What conclusion should I make about the two manufacturing processes?
A. The first method is better.
B. The second method is better.
C. Both methods are equivalent.
3. In a sample of 20 items, I found 6 defective. In constructing a confidence interval for the proportion of defectives, I should use
A. the plus four method.
B. the large sample interval.
C. neither of the two methods.