if there is a total volume of 5,090km3 of liquid surface fresh water, what volume is found in swamps?
1 answer:
You might be interested in
Answer:
A sample of 499 is needed.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error is given by:
In this question, we have that:
90% confidence level
So , z is the value of Z that has a pvalue of
, so
.
How large a sample would be required in order to estimate the fraction of tenth graders reading at or below the eighth grade level at the 90% confidence level with an error of at most 0.03
We need a sample of n, which is found when . So
Rounding up
A sample of 499 is needed.
That probability is about 20.5%.
