Sample Size Calculator
Determine the sample size needed to estimate means or proportions with desired precision.
Required Sample Size
35
Infinite population
Parameters
Desired Margin of Error± 5
Confidence Level95%
Importance of Sample Size
An adequate sample size ensures results are accurate and reliable. Too small samples may fail to detect real effects, while too large samples waste resources.
Factors to Consider
Sample size depends on desired margin of error, confidence level, expected variability, and for finite populations, the population size.
Proportion of 0.5
When you don't know the expected proportion, use 0.5 (50%). This maximizes variance and gives the most conservative sample size.