Tutorial (from the start) [Power / Sample Size]

posted by Alyssa – Malaysia, 2020-05-12 06:05 (1440 d 11:39 ago) – Posting: # 21426
Views: 7,076

Hi Helmut,

Yeah, you are right, i din't install powerTOST. :-|

Once i installed and i follow from the the start, i managed to get up to :-

Sample size search
 n     power
36   0.7642
39   0.7950
42   0.8198


Then i continued with the following command but it appeared error:-

> # partial replicate, 3- and 4-period full replicate designs
> designs <- c("2x3x3", "2x2x3", "2x2x4")
> # desired powers
> target  <- c(0.80, 0.85, 0.90)
> # assign a data.frame of results
> res     <- data.frame(design = rep(designs, each = length(target)),
+                       target = target, n = NA, power = NA)
> # loop over the rows, apply the defaults:
> # T/R-ratio 0.90, 100,000 simulated studies
> for (j in 1:nrow(res)) {
+   res[j, 3:4] <- sampleN.scABEL(CV = CV, design = res$design[j],
+                                 targetpower = res$target[j],
+                                 print = FALSE, details = FALSE)[8:9] + }
Error in match.arg(design) : 'arg' must be NULL or a character vector
> print(res, row.names = FALSE)
 design target  n power
  2x3x3   0.80 NA    NA
  2x3x3   0.85 NA    NA
  2x3x3   0.90 NA    NA
  2x2x3   0.80 NA    NA
  2x2x3   0.85 NA    NA
  2x2x3   0.90 NA    NA
  2x2x4   0.80 NA    NA
  2x2x4   0.85 NA    NA
  2x2x4   0.90 NA    NA


May i know what is this error about? Thank you.


Edit: Code and results BBCoded; see also this post #10[Helmut]

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