Dear Paulo
You did realise that if you type prop.trend.test you get
function (x, n, score = seq_along(x))
{
method <- "Chi-squared Test for Trend in Proportions"
dname <- paste(deparse1(substitute(x)), "out of",
deparse1(substitute(n)),
",\n using scores:", paste(score, collapse = " "))
x <- as.vector(x)
n <- as.vector(n)
p <- sum(x)/sum(n)
w <- n/p/(1 - p)
a <- anova(lm(freq ~ score, data = list(freq = x/n, score =
as.vector(score)),
weights = w))
chisq <- c(`X-squared` = a["score", "Sum Sq"])
structure(list(statistic = chisq, parameter = c(df = 1),
p.value = pchisq(as.numeric(chisq), 1, lower.tail = FALSE),
method = method, data.name = dname), class = "htest")
}
<bytecode: 0x0000021d81d4c850>
<environment: namespace:stats>
Does that help?
Michael
On 11/11/2025 18:27, Paulo Barata wrote:> To the R-Help list,
>
> About the prop.trend.test function, in the package stats.
>
> What calculations exactly does that function perform? What test is
> actually carried out? May I have some reference for the calculations
> performed by that function?
>
> I would like to suggest that some references (one or more) be included
> in the Help file for the function.
>
> Thank you very much.
>
> Paulo Barata
>
> Rio de Janeiro - Brazil
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide https://www.R-project.org/posting-
> guide.html
> and provide commented, minimal, self-contained, reproducible code.
--
Michael Dewey
There's a worked example of the procedure in Altman: Practical Statistics for Medical Research, also featured in help(ISwR::caesarean). (I have forgotten the origin of example(prop.trend.test), though. If I ever knew it. Apparently it is the same as in help(prop.test): Fleiss(1981), p.139, but I don't have that edition to hand and I don't see it in Fleiss(1973).) -pd> On 12 Nov 2025, at 11.55, Michael Dewey <lists at dewey.myzen.co.uk> wrote: > > Dear Paulo > > You did realise that if you type prop.trend.test you get > > function (x, n, score = seq_along(x)) > { > method <- "Chi-squared Test for Trend in Proportions" > dname <- paste(deparse1(substitute(x)), "out of", deparse1(substitute(n)), > ",\n using scores:", paste(score, collapse = " ")) > x <- as.vector(x) > n <- as.vector(n) > p <- sum(x)/sum(n) > w <- n/p/(1 - p) > a <- anova(lm(freq ~ score, data = list(freq = x/n, score = as.vector(score)), > weights = w)) > chisq <- c(`X-squared` = a["score", "Sum Sq"]) > structure(list(statistic = chisq, parameter = c(df = 1), > p.value = pchisq(as.numeric(chisq), 1, lower.tail = FALSE), > method = method, data.name = dname), class = "htest") > } > <bytecode: 0x0000021d81d4c850> > <environment: namespace:stats> > > Does that help? > > Michael > > On 11/11/2025 18:27, Paulo Barata wrote: >> To the R-Help list, >> About the prop.trend.test function, in the package stats. >> What calculations exactly does that function perform? What test is actually carried out? May I have some reference for the calculations performed by that function? >> I would like to suggest that some references (one or more) be included in the Help file for the function. >> Thank you very much. >> Paulo Barata >> Rio de Janeiro - Brazil >> ______________________________________________ >> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide https://www.R-project.org/posting- guide.html >> and provide commented, minimal, self-contained, reproducible code. > > -- > Michael Dewey > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide https://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.-- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com
Dear Michael, Yes, I forgot about that, just typing the function's name. My fault, I am sorry. Thank you very much for your reply. Best regards, Paulo ------------------------------------------------------- On 12-Nov-25 7:55, Michael Dewey wrote:> Dear Paulo > > You did realise that if you type prop.trend.test you get > > function (x, n, score = seq_along(x)) > { > ??? method <- "Chi-squared Test for Trend in Proportions" > ??? dname <- paste(deparse1(substitute(x)), "out of", deparse1(substitute(n)), > ??????? ",\n using scores:", paste(score, collapse = " ")) > ??? x <- as.vector(x) > ??? n <- as.vector(n) > ??? p <- sum(x)/sum(n) > ??? w <- n/p/(1 - p) > ??? a <- anova(lm(freq ~ score, data = list(freq = x/n, score = as.vector(score)), > ??????? weights = w)) > ??? chisq <- c(`X-squared` = a["score", "Sum Sq"]) > ??? structure(list(statistic = chisq, parameter = c(df = 1), > ??????? p.value = pchisq(as.numeric(chisq), 1, lower.tail = FALSE), > ??????? method = method, data.name = dname), class = "htest") > } > <bytecode: 0x0000021d81d4c850> > <environment: namespace:stats> > > Does that help? > > Michael > > On 11/11/2025 18:27, Paulo Barata wrote: >> To the R-Help list, >> >> About the prop.trend.test function, in the package stats. >> >> What calculations exactly does that function perform? What test is actually carried out? May I have some reference for the calculations performed by that function? >> >> I would like to suggest that some references (one or more) be included in the Help file for the function. >> >> Thank you very much. >> >> Paulo Barata >> >> Rio de Janeiro - Brazil >> >> ______________________________________________ >> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide https://www.R-project.org/posting- guide.html >> and provide commented, minimal, self-contained, reproducible code. >