Sample Size
1. The problem is to calculate the sample size $n$ using the formula:
$$n = \frac{Z^2 \times p \times q}{e^2}$$
where $Z = 1.96$, $p = 0.247$, $q = 1 - p = 1 - 0.247 = 0.753$, and $e = 0.05$.
2. Substitute the values into the formula:
$$n = \frac{(1.96)^2 \times 0.247 \times 0.753}{(0.05)^2}$$
3. Calculate each part step-by-step:
- Calculate $Z^2$: $1.96^2 = 3.8416$
- Calculate $p \times q$: $0.247 \times 0.753 = 0.186\,091$
- Calculate $e^2$: $0.05^2 = 0.0025$
4. Now substitute these values back:
$$n = \frac{3.8416 \times 0.186091}{0.0025}$$
5. Multiply numerator:
$$3.8416 \times 0.186091 = 0.7149$$
6. Divide by denominator:
$$n = \frac{0.7149}{0.0025} = 285.96$$
7. Since sample size must be a whole number, round up:
$$n = 286$$
**Final answer:** The required sample size is $286$.