Re: [R] Missing data (Na) and chi-square tests

[Rui Barradas]

Hello,

Also, since the values are always 0/1, this should also do it.

with( dat, table( Rash, Hypotension ) )

Hope this helps,

Rui Barradas

Em 09-10-2012 00:36, David Winsemius escreveu:

On Oct 8, 2012, at 9:06 AM, Rerda wrote:

Dear Rui and David
Thank you very much for taking your time to look at my problem.
However, I still cannot seem to figure it out.

I think that you David are corect in your assumption of how my data is
structured. The data in the two columns that I need to cross-table is either
1 or 0.
I made a mistanke in the formula that I sent to you. The one I use is:
data <- matrix(c(sum(!Variable[Group....==1]), sum(Variable[Group....==1]),
sum(!Variable[Group....==0]), sum(Variable[Group....==0])),2,2)

Hardly seems surprising that is not working, ... the is no "Group...." column 
in the data. Furthermore you would not need to use sum( !Variable[Group....==1] as well 
as sum(Variable[Group....==1]). The `table` function will do that for you.

Given my personal memory of having a hypotensive episode as I stood at the 
counter of a pharmacy asking for epinephrine and a syringe to treat my 
urticarial reaction to shellfish, I picked these two:

with( MyData, table( Rash= as.logical(Rash), Hypotension = 
as.logical(Hypotension) ) )

        Hypotension
Rash    FALSE TRUE
   FALSE     3    7
   TRUE      7    3

Best;
David.

This is the output of >dput( head(MyData, 20) ):

structure(list(Patient.nr = c(1L, 3L, 4L, 5L, 6L, 7L, 9L, 10L,
11L, 12L, 13L, 14L, 15L, 16L, 19L, 20L, 21L, 22L, 23L, 24L),
    DAAC.... = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L,
    0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L), TAA = c(0L, 0L, 0L,
    0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L,
    0L, 0L), Sex = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L,
    0L, 0L, 1L, 0L, 0L, 1L, 1L, 0L, 0L, 0L), Alder = c(1L, 6L,
    3L, 3L, 6L, 6L, 2L, 6L, 5L, 2L, 6L, 4L, 6L, 2L, 2L, 5L, 3L,
    6L, 6L, 6L), Reak.1 = structure(c(2L, 1L, 2L, 2L, 1L, 2L,
    2L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 2L), .Label = c("0",
    "1", "na"), class = "factor"), Reak.2 = structure(c(1L, 1L,
    1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 1L, 1L, 2L, 1L, 1L, 2L, 1L,
    2L, 1L, 1L), .Label = c("0", "2", "na"), class = "factor"),
    Reak.3 = structure(c(1L, 2L, 1L, 1L, 1L, 1L, 1L, 2L, 2L,
    1L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 1L), .Label = c("0",
    "3", "na"), class = "factor"), Reak.4 = structure(c(1L, 1L,
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
    1L, 1L, 1L), .Label = c("0", "4", "na"), class = "factor"),
    Tryptase = structure(c(1L, 1L, 1L, 3L, 1L, 3L, 1L, 2L, 2L,
    1L, 3L, 3L, 1L, 3L, 3L, 3L, 3L, 3L, 2L, 1L), .Label = c("0",
    "1", "na"), class = "factor"), Hypotension = c(0L, 1L, 0L,
    0L, 1L, 0L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 0L, 0L, 0L, 0L, 0L,
    1L, 0L), Tachycardia = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L,
    1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L), Br.spasm. = c(0L,
    1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L,
    0L, 0L, 0L, 0L), Angioedema = c(0L, 0L, 0L, 1L, 0L, 1L, 0L,
    0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L), Urticaria = c(0L,
    0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L,
    0L, 0L, 0L, 0L), Flush. = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L,
    0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L), Rash = c(1L,
    0L, 1L, 0L, 1L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 1L, 1L, 1L, 0L,
    1L, 1L, 0L, 1L), Pruritus = c(0L, 0L, 0L, 0L, 0L, 0L, 0L,
    1L, 0L, 1L, 0L, 1L, 0L, 1L, 0L, 0L, 1L, 1L, 0L, 0L), Transf. = c(0L,
    0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L,
    0L, 0L, 0L, 0L)), .Names = c("Patient.nr", "DAAC....", "TAA",
"Sex", "Alder", "Reak.1", "Reak.2", "Reak.3", "Reak.4", "Tryptase",
"Hypotension", "Tachycardia", "Br.spasm.", "Angioedema", "Urticaria",
"Flush.", "Rash", "Pruritus", "Transf."), row.names = c(NA, 20L
), class = "data.frame")

And I still can get it to work.
Is it possible to put is.na(Variable) or something into my formula?

I understand if it is to difficult to figure it put.
Thank you very much

Kind Regards Gerda



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David Winsemius, MD
Alameda, CA, USA

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and provide commented, minimal, self-contained, reproducible code.