How to calculate sample size?

Hi For a study I Need to determine the sample size. We will do several measurements and should not be significantly above the defined threshold of 3mm. A previous study showed a mean of 1.32 with the std of 0.98. Significance (Alpha) and power (1-beta) are as usual 0.05 & 0.8. Can I do it that way or am I completely wrong? -> sampsize= sampsizepwr('t',[1.32 0.98],3,0.80)

Answer 1

[Riccardo Monterubbianesi]

Hello, at the end, Is this formula correct?