Hi Everyone,   I am currently learning sample size calculations using SAS and I came across this question:   Under ideal packaging conditions, the concentration of the active ingredient in a vacuum packed dry powdered product should be independent of storage temperature and humidity at the time of packaging and there should be no difference between initial and end-of-shelf-life concentrations. An experiment to study the active ingredients concentration is planned using a 3x2x2 experiment design in temperature, humidity, and age, respectively. The variable levels are: 20°C, 25°C, and 30°C for temperature; 25 and 50 percent for humidity, and 0 and 6 months for age. Determine the number of replicates are required to detect an effect size of 30 ppm with 90% power when the standard error of the model is expected to be 20 ppm.   I do not know how to approach this problem since I do not have any data to use for sample size calculations. I tried using proc glmpower but it would require a set of data in order to calculate. Is there a way to find sample size with just effect size and standard error?   Thanks in advance!   ... View more