1. **State the problem:** We want to find how many more students need to be surveyed to achieve a margin of error (ME) of 4% when the proportion of students who traveled abroad is 57%.
2. **Formula for margin of error in proportion:**
$$ ME = z \times \sqrt{\frac{p(1-p)}{n}} $$
where $p$ is the sample proportion, $n$ is the sample size, and $z$ is the z-score for the confidence level.
3. **Identify values:**
- $p = 0.57$
- $ME = 0.04$
- For a 95% confidence level, $z = 1.96$
- Current sample size $n_0 = 265265$
4. **Rearrange formula to solve for $n$:**
$$ n = \frac{z^2 \times p(1-p)}{ME^2} $$
5. **Calculate $n$:**
$$ n = \frac{1.96^2 \times 0.57 \times (1-0.57)}{0.04^2} $$
6. **Calculate numerator:**
$$ 1.96^2 = 3.8416 $$
$$ 0.57 \times 0.43 = 0.2451 $$
$$ 3.8416 \times 0.2451 = 0.9413 $$
7. **Calculate denominator:**
$$ 0.04^2 = 0.0016 $$
8. **Calculate $n$:**
$$ n = \frac{0.9413}{0.0016} = 588.3125 $$
9. **Determine how many more students to survey:**
Current surveyed: 265265
Needed total: 589 (rounded up from 588.3125)
Since the current sample size is much larger than needed, no additional students are required to achieve the margin of error of 4%.
Margin Error Fc2161
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