| expected {epitools} | R Documentation |
Assuming independence, calculates expected values in a matrix or table.
expected(x)
x |
is a matrix or table |
Assuming independence, calculates expected values in a matrix or table.
expected values
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Tomas Aragon, aragon@berkeley.edu, http://www.medepi.net/aragon
Steve Selvin (2001), Epidemiologic Analysis: A Case-Oriented Approach, Oxford University Press
See also margin.table
##From Selvin, 2001, p.2
##year = year of birth
##one+ = one or more congenital defects
##one = one congenital defect
dat <- scan()
369 460
434 434
506 487
521 518
526 488
605 481
649 477
733 395
688 348
##observed
oi <- matrix(dat, nrow =2)
colnames(oi) <- 1983:1991
rownames(oi) <- c("one+", "one")
##expected
ei <- expected(oi)
##Pearson chi-square test
chi2.T <- sum((oi - ei)^2/ei)
pchisq(q = chi2.T, df = 8, lower.tail = FALSE)