Optionalalternative"two.sided" (default), "less" or "greater"; unambiguous abbreviations are accepted.
OptionaldEffect size d (Cohen's d), or "small", "medium", "large".
OptionalnNumber of observations (per group, or of pairs).
OptionalpowerPower of the test.
OptionalsigSignificance level. Default 0.05.
Optionaltype"two.sample" (default), "one.sample" or "paired".
Options for pwrTTest. The quantity given as
null(or omitted, exceptsigLevel) is solved for.