How can I calculate the margin of error for a sample proportion in Excel without a dedicated function?

For a sample proportion, the margin of error formula is approximately: `Z * SQRT(p * (1-p) / n)`, where 'Z' is the Z-score for your desired confidence level (e.g., 1.96 for 95% confidence), 'p' is the sample proportion, and 'n' is the sample size. You'll need to calculate 'p' and use `SQRT` and multiplication/division in Excel.