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**Sample Size calculator Formula:**

ss = Z^{2} × P × (1 - P) / C^{2}

Where:

**Z**: Z value (1.96 for 95% confidence level, 2.58 for 99%)

**P**: Choice percentage ( 0 - 100 )

**C**: Confidence Interval ( 0 - 100 )

If population is small, the sample size need adjustment as follows, otherwise, just leave the population field empty:

ss = ss / ( 1 + (ss - 1)/population)