# [R] Problems with Shapiro Wilk's test of normality.

Fredrik Karlsson dargosch at gmail.com
Thu Nov 10 10:56:34 CET 2005

Never mind,

I solved it myself. It was an NA problem.

/Fredrik

On 11/9/05, Fredrik Karlsson <dargosch at gmail.com> wrote:
> Hi,
>
> I am trying to create a table with information from Shapiro Wilk's
> test of normality.
> However, it fails due to lack of sample size, it says, but the way I
> see it, this is not a problem.
> (See the table of sample sizes (almost) at the bottom).
>
> Applying a different function using a similar ftable call is not a
> problem (See the bottom table).
>
> This is R 2.1.0 on Linux (Gentoo).
>
> /Fredrik
>
> > shapiro.p.value <- function(x){
> +   if(length(! is.na(x)) > 3 & length(! is.na(x)) < 5000 ){
> +     p <- shapiro.test(x)$p.value > + return(p) > + }else{ > + return(NA) > + } > + } > > > > distribution.table.fun <- function(x,na.rm=T,digits=1){ > + > + if(length(! is.na(x)) > 3 & length(! is.na(x)) < 5000){ > + # shapTest <- shapiro.test(x) > + # W <- shapTest$statistic
> +     W <- "W"
> +   }
> +
> +
> +
> +   shap <- shapiro.p.value(x)
> +   stars <- ''
> +   premark <- ''
> +   postmark <- ''
> +   if(length(x) < 10){
> +       premark <- '\\textit{'
> +       postmark <- '}'
> +   }
> +
> +   #skapa stjärnor
> +   if(! is.na(shap)){
> +     if( shap <= 0.001 ){
> +       stars <- '***'
> +     }else{
> +       if( shap <= 0.01 ){
> +         stars <- '**'
> +       }else{
> +         if( shap <= 0.05 ){
> +           stars <- '*'
> +         }
> +
> +       }
> +
> +     }
> +
> +     outstr <- paste(premark,'W=',W,',p=',shap,postmark,stars,sep="")
> +   }
> +   else{
> +     outstr <-  ""
> +   }
> +
> +
> +   return(outstr)
> +
> + }
> >
> > ftable(tapply(aspvotwork$ampratio,list(Place=aspvotwork$Place,Age=aspvotwork$agemF,voicetype=aspvotwork$Type),FUN="length" ))
>                voicetype Voiced Voiceless unaspirated Voiceless aspirated
> Place  Age
> Velar  18 - 24               44                    41                  34
>        24 - 30               70                    81                  71
>        30 - 36               59                    66                  64
>        36 - 42               25                    27                  22
>        42 - 48               22                    23                  23
>        48 - 54               12                     9                   7
> Dental 18 - 24               48                    61                  54
>        24 - 30               82                   101                  89
>        30 - 36               57                    82                  72
>        36 - 42               19                    31                  34
>        42 - 48               25                    33                  31
>        48 - 54               10                    12                  14
> Labial 18 - 24               74                   141                  84
>        24 - 30              142                   264                 162
>        30 - 36              124                   213                 148
>        36 - 42               50                    91                  50
>        42 - 48               49                    82                  64
>        48 - 54               17                    26                  16
> > ftable(tapply(aspvotwork$ampratio,list(Place=aspvotwork$Place,Age=aspvotwork$agemF,voicetype=aspvotwork$Type),FUN="distribution.table.fun",digits=4))
> Error in shapiro.test(x) : sample size must be between 3 and 5000
> >
>   > ftable(tapply(aspvotwork$ampratio,list(Place=aspvotwork$Place,Age=aspvotwork$agemF,voicetype=aspvotwork$Type),FUN="mean",digits=4,na.rm=TRUE
> ))
>                voicetype    Voiced Voiceless unaspirated Voiceless aspirated
> Place  Age
> Velar  18 - 24           0.4816810             0.4461307           0.4513994
>        24 - 30           0.5289028             0.4778686           0.4888445
>        30 - 36           0.5452949             0.5208633           0.4756369
>        36 - 42           0.5631310             0.4697789           0.4709779
>        42 - 48           0.4968318             0.4174068           0.4088855
>        48 - 54           0.3057712             0.4483639           0.4561953
> Dental 18 - 24           0.4058078             0.4596251           0.4091731
>        24 - 30           0.4609731             0.4502778           0.4483340
>        30 - 36           0.5095430             0.4726149           0.4315419
>        36 - 42           0.4935719             0.4687774           0.4528758
>        42 - 48           0.4344465             0.4220429           0.4362018
>        48 - 54           0.3697664             0.4338549           0.4897856
> Labial 18 - 24           0.4327926             0.4879985           0.4503917
>        24 - 30           0.5309634             0.4839031           0.5927699
>        30 - 36           0.4094516             0.4444757           0.3964693
>        36 - 42           0.5010130             0.4855550           0.4540598
>        42 - 48           0.4949510             0.4329442           0.3935921
>        48 - 54           0.5217893             0.5124186           0.5011346
> >
>

--
My Gentoo + PVR-350 + IVTV + MythTV blog is on
http://gentoomythtv.blogspot.com/