50 lines
1.4 KiB
R
50 lines
1.4 KiB
R
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## glm.nb with weights
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library(MASS)
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yeast <- data.frame(cbind(numbers = 0:5, fr = c(213, 128, 37, 18, 3, 1)))
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attach(yeast)
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n <- rep(numbers, fr)
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## fitting using glm.nb with weights - wrong results in 7.2-18
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yeast2.fit <- glm.nb(numbers~1, link = log, weights=fr)
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summary(yeast2.fit)
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## fitting extending the vector and using glm.nb - correct result ##
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yeast3.fit<-glm.nb(n~1, link = log)
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summary(yeast3.fit)
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stopifnot(all.equal(deviance(yeast2.fit), deviance(yeast3.fit)))
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stopifnot(all.equal(yeast2.fit$theta, yeast3.fit$theta))
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detach(yeast)
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# another one, corrected in 7.2-43
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set.seed(13245)
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x <- c(-5:5)
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mu <- exp(1 + 0.1*x)
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y <- rnegbin(length(mu), mu = mu, theta = 1.5)
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dat <- data.frame(x, y)
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dat2 <- dat[rep(1:11, each=2), ]
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w <- round(runif(11),2)
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dat2$w <- as.vector(rbind(w, 1-w))
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fm2 <- glm.nb(y ~ x, dat)
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gm2 <- glm.nb(y ~ x, dat2, weights = w)
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summary(fm2)
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summary(gm2) # failed before
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stopifnot(all.equal(fm2$theta, gm2$theta)) # differed
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stopifnot(all.equal(deviance(fm2), deviance(gm2)))
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fm3 <- glm(y ~ x, negative.binomial(theta = fm2$theta), dat)
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gm3 <- glm(y ~ x, negative.binomial(theta = fm2$theta), dat2, weights =w)
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summary(fm3)
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summary(gm3)
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stopifnot(all.equal(deviance(fm3), deviance(gm3)))
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fit <- glm.nb(Days ~ Sex/(Age + Eth*Lrn), data = quine)
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set.seed(1)
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simulate(fit, nsim=5)[1:10, ]
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if(getRversion() >= "2.9.0") {
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fit2 <- glm.convert(fit)
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set.seed(1)
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print(simulate(fit2, nsim=5)[1:10, ])
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}
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