2025-01-12 00:52:51 +08:00

110 lines
3.9 KiB
R

library(survival)
aeq <- function(x, y, ...) all.equal(as.vector(x), as.vector(y), ...)
fit1 <- lm(skips ~ Opening + Solder + Mask + PadType + Panel,
data=solder)
y1 <- yates(fit1, "Opening")
temp <- levels(solder$Opening)
tpred <- matrix(0., nrow(solder), 3)
for (i in 1:3) {
tdata <- solder
tdata$Opening <- temp[i]
tpred[,i] <- predict(fit1, newdata=tdata)
}
all.equal(y1$estimate[,"pmm"], colMeans(tpred))
# This fit is deficient: there are no Opening=L and Mask=A6 obs
# The MPV for Mask=A6 and Opening L will therefore be NA, as well
# as for all levels of Solder, but we can compute the others.
# Solder will be NA for all levels
fit2 <- lm(skips ~ Opening*Mask + Solder,
data=solder)
y2a <- yates(fit2, "Mask", population="factorial")
y2b <- yates(fit2, "Opening", population="factorial")
y2c <- yates(fit2, "Solder", population="factorial")
# The predict.lm function gives correct predictions for estimable
# functions (all but L,A6) and nonsense for others. It knows that
# some are not estimable due to the NA coefficients, but not which ones,
# so always prints a warning. Hence the suppressWarnings call.
tdata <- do.call(expand.grid, fit2$xlevels[1:3])
temp <- levels(solder$Mask)
tpreda <- matrix(0., nrow(tdata), length(temp),
dimnames=list(NULL, temp))
for (i in seq_along(temp)) {
tdata$Mask <- temp[i]
suppressWarnings(tpreda[,i] <- predict(fit2, newdata=tdata))
}
tpreda[,"A6"] <- NA # the A6 estimate is deficient
aeq(y2a$estimate[,"pmm"], colMeans(tpreda))
tdata <- do.call(expand.grid, fit2$xlevels[1:3])
temp <- levels(solder$Opening)
tpredb <- matrix(0., nrow(tdata), length(temp),
dimnames=list(NULL, temp))
for (i in seq_along(temp)) {
tdata$Opening <- temp[i]
suppressWarnings(tpredb[,i] <- predict(fit2, newdata=tdata))
}
tpredb[,"L"] <- NA
aeq(y2b$estimate[,"pmm"], colMeans(tpredb))
# Solder should be all NA
all(is.na(y2c$estimate[,"pmm"]))
# Tests for Solder are defined for a non-factorial population, however.
# the [] below retains the factor structure of the variable, where the
# runs above did not. R gets prediction correct both ways.
y2d <- yates(fit2, ~Solder)
temp <- levels(solder$Solder)
tdata <- solder
tpredd <- matrix(0, nrow(tdata), length(temp),
dimnames=list(NULL, temp))
for (i in seq_along(temp)) {
tdata$Solder[] <- temp[i]
suppressWarnings(tpredd[,i] <- predict(fit2, newdata=tdata))
}
aeq(y2d$estimate$pmm, colMeans(tpredd))
#
# Verify that the result is unchanged by how dummies are coded
# The coefs move all over the map, but predictions are unchanged
fit3 <- lm(skips ~ C(Opening, contr.helmert)*Mask + C(Solder, contr.SAS),
data=solder)
y3a <- yates(fit3, ~Mask, population='yates')
equal <- c("estimate", "test", "mvar")
all.equal(y3a[equal], y2a[equal])
tdata <- do.call(expand.grid, fit2$xlevels[1:3]) # use orignal variable names
temp <- levels(solder$Mask)
cpred <- matrix(0., nrow(tdata), length(temp),
dimnames=list(NULL, temp))
for (i in seq_along(temp)) {
tdata$Mask <- temp[i]
suppressWarnings(cpred[,i] <- predict(fit3, newdata=tdata))
}
aeq(cpred[, temp!="A6"], tpreda[, temp!= "A6"]) # same predictions
all.equal(y3a$estimate, y2a$estimate)
y3b <- yates(fit3, ~Opening, population='yates')
# column names will differ
all.equal(y3b$estimate, y2b$estimate, check.attributes=FALSE)
y3d <- yates(fit3, ~Solder)
for (i in 1:3) {
print(all.equal(y3d[[i]], y2d[[i]], check.attributes=FALSE))
}
# Reprise this with a character variable in the model
sdata <- solder
sdata$Mask <- as.character(sdata$Mask)
fit4 <- lm(skips ~ Opening*Mask + Solder, data=sdata)
y4a <- yates(fit4, ~ Mask, population= "yates")
y4b <- yates(fit4, ~ Opening, population= "yates")
y4d <- yates(fit4, ~ Solder)
equal <- c("estimate", "tests", "mvar", "cmat")
all.equal(y2a[equal], y4a[equal]) # the "call" component differs
all.equal(y2b[equal], y4b[equal])
all.equal(y2d[equal], y4d[equal])