whereNis the population size,ris the fraction of responses that you are interested in, andZ(c/100) is thecritical valuefor the confidence levelc. If you'd like to see how we perform the calculation, view the page source. This calculation is based on theNormal distribution, and assumes you...
如果是问卷用随机抽样方法，可参考随机抽样公式：N=Z2σ2D2 N为样本量、Z为置信区间、d为抽样误差范...
Add Calculation-Allows you to create a new calculated value for a single record or multiple records in the current database. Next Record-Changes the data displayed to that of the next record in the database. Previous Record-Changes the data displayed to that of the previous record in the da...
Survey software tools for online surveys: Web surveys, Email surveys, web survey software scripts for online surveys