The square of a number is 12 less than 7 times the number. What is the number
1 answer:
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Answer:
We need a sample size of at least 1161.
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 for the interval is:
For this problem, we have that:
90% confidence level
So , z is the value of Z that has a pvalue of
, so
.
How large a sample should she take?
We need a sample size of at least n.
n is found when
So
Rounding up
We need a sample size of at least 1161.