I think '2' is the only one that works.
Answer: 
Step-by-step explanation:
The confidence interval for population proportion is given by :-

Given : Sample size : 
The proportion of people selected consumers who had opportunities to send in a rebate claim form after purchasing a product said they never did so =
Significance level : 
Critical value : 
Now, the 95% confidence Interval for the true proportion of such consumers who never apply for a rebate will be :-

Hence, a confidence Interval for the true proportion of such consumers who never apply for a rebate .
Answer:
b = 7
Step-by-step explanation:
-144 = 8(3-3b)
-18 = 3-3b
-21 = -3b
b = 7
11% or 3/9 should be right. Hope it helps :)
I think the answer is false