Sample size in r program, sample size in r programming language, sample size in research, how to determine sample size in research, problems with small sample size in research, small sample size in research, sample size in research proposal, how to calculate sample size in excel, importance of sample size in research, sample size in r, sample size calculator, sample size formula, raosoft sample size calculator, sample size in research, sample size table, sample size calculation formula, sample size determination formula,