Keng - Knock Errors Off Nice Guesses

Miscellaneous functions and data used in Qingyao's psychological research and teaching. Keng currently has a built-in dataset depress, and could (1) scale a vector, (2) test the significance and compute the cut-off values of Pearson's r without raw data, (3) compare lm()'s fitted outputs using R-squared, f_squared, post-hoc power, and PRE (Proportional Reduction in Error, also called partial R-squared or partial Eta-squared). (4) Calculate PRE from partial correlation, Cohen's f, or f_squared. (5) Compute the post-hoc power for one or a set of predictors in regression analysis without raw data, (6) Plan the sample size for one or a set of predictors in regression analysis.