Estimating a sample size for your project can be confusing, complicated and frustrating. When it come down to creating the final plan, it’s a good idea to get an expert’s opinion. But while you are thinking things over there are some good online resources to get you started.
Sample Size Calculator offers both sample size and confidence interval calculation. While this tool does not offer many parameters to control the level of precision of the calculation, it includes easy-to-understand definitions of common statistical terminology.soft
Raosoft presents a sample size calculator that takes into account the margin of error, the confidence level, and the response distribution. It also offers to show side by side what the margin of error would be like with various sample sizes.
SampleCalc has the capacity to calculate both sample size and the margin of error. Among the sample size calculation tools listed here, this is the tool with the most control over the statistical parameters (therefore the most precise). It is also the only one available both in English and in French. SampleCalc takes into account the confidence level, the proportion for the calculation of the margin of error, the design effect value, the margin of error and the expected response rate.
DeffCalc estimates the design effect value due to sample stratification.