Emily earned a grade of 80% on a math test that had 20 problems. How many problems on this test did she answer correctly? If Joh
2 answers:
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Answer:
You must survey 784 air passengers.
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:
95% confidence level
So , z is the value of Z that has a pvalue of
, so
.
Assume that nothing is known about the percentage of passengers who prefer aisle seats.
This means that , which is when the largest sample size will be needed.
Within 3.5 percentage points of the true population percentage.
We have to find n for which M = 0.035. So
You must survey 784 air passengers.