Answer:
The 85% confidence interval is (0.2187, 0.2613).
Step-by-step explanation:
We have a large sample of size n = 830 Americans over 45. We have observed that 631 people don't smoke. Let p be the population proportion of Americans over 45 who smoke. An point estimate of p is
and an estimate of the standard deviation of
is
= 0.0148. Therefore, because we have a large sample, the 85% confidence interval for the population proportion is given by
where
is the 7.5th quantile of the standard normal distribution, i.e., -1.4395. Therefore the 85% confidence interval is
or equivalently (0.2187, 0.2613).
Answer:
12 tablespoons of butter
Step-by-step explanation:
Create a proportion:
= 
Cross multiply:
1/3x = 4
x = 12
= 12 tablespoons of butter
You can just multiply the top and the bottom by the same number, and you will get equivalent fractions.
This is the correct answer: 3x^3 - x^2 + 6x - 9