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 <[email protected]> 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 >> ______________________________________________ >> [email protected] 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 > > ______________________________________________ > [email protected] 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: [email protected] Priv: [email protected] ______________________________________________ [email protected] 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.
