True.

When no reasonable estimate of the population proportion $p$ is available, we often use $\hat{p} = 0.5$ to calculate the required sample size $n$. This is because $\hat{p} = 0.5$ maximizes the sample size, ensuring the sample is large enough to achieve the desired confidence level and margin of error.

Would you like more details or have any questions?

1. Why does $\hat{p} = 0.5$ maximize the required sample size?
2. How is the formula for sample size derived for interval estimation of a population proportion?
3. What is the relationship between margin of error and sample size in proportion estimation?
4. How do confidence levels affect sample size in interval estimation?
5. What happens if a preliminary estimate for $p$ is available?

Tip: Using $\hat{p} = 0.5$ provides a conservative estimate when the actual proportion is unknown, helping to avoid underestimating the required sample size.