Question

Two studies were completed in California. One study in northern California involved 1,000 patients; 74% of them experienced flulike symptoms during the month of December. The other study, in southern California, involved 500 patients; 34% of them experienced flulike symptoms during the same month. Which study has the smallest margin of error for a 98% confidence interval?

Answer 1

The northern California study with a margin of error of 3.2%.
The southern California study with a margin of error of 3.2%.
The northern California study with a margin of error of 4.9%.
The southern California study with a margin of error of 4.9%.

Answer 2

The margin of error is found from
\[\large 2.33\sqrt{\frac{p(1-p)}{n}}\]
where p is the sample proportion expressed as a decimal.
Therefore the margin of error for the northern California study is
\[\large 2.33\sqrt{\frac{0.74\times0.26}{1000}}=you\ can\ calculate.\]
Now you need to use the same procedure to find the margin of error for the southern California study.

Answer 3

so whats the answer?

Answer 4

@kropot72

Answer 5

because both A and D are the answer but only one can be chosen!

Answer 6

ok, A is the correct choice!

Answer 7

for future users!