Power analysis for 2 independent means

If you have 2 different groups and you are going to compare a numerical variable in these groups, you can estimate the minimum number of participants needed in each group using the expected means and standard deviations you determined from the literature.

Required information

α error: shows the significance level of the p value. Choose between 0.05 and 0.01.

Strength (1-β): Select between 80% and 90% for targeted strength  

Mean and standard deviation of group 1:

Mean and standard deviation of group 2:

Sample calculation: In order to find a significant difference at the 0.05 level and with 80% power when the values obtained from the literature for one of the groups are 10±5 and the other is 12±5, the information should be entered into the application as follows to calculate the minimum number of participants required in each group.