Answer:
We need at least 243 stores.
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 of the interval is:
For this problem, we have that:
95% confidence level
So , z is the value of Z that has a pvalue of , so .
Determine the number of stores that must be sampled in order to estimate the true proportion to within 0.04 with 95% confidence using the large-sample method.
We need at least n stores.
n is found when M = 0.04. So
Rounding up
We need at least 243 stores.
3x(3x-2y)
you have to find a common factor between the two numbers. in this case it's three, so you just divide each number by three.