On 12/2/2013 10:12 AM, Duncan Murdoch wrote:
dbinom can take vector inputs for the parameters, so this would be a
bit simpler:
x <- seq(0,12)
x <- rep(x, 4)
p <- rep(c(1/6, 1/3, 1/2, 2/3), each=13)
bin.df <- data.frame(x, prob = dbinom(x, 12, p), p)
Thanks, Duncan
What I was missing was how dbinom() could use vector inputs for both x & p.
Using expand.grid() gives me what I want and is more
general for my purposes. The main purpose of making p a factor is to
facilitate
plots of prob ~ x|p.
XP <-expand.grid(x=0:12, p=c(1/6, 1/3, 1/2, 2/3))
bin.df <- data.frame(XP, prob=dbinom(XP[,"x"], 12, XP[,"p"]))
bin.df$p <- factor(bin.df$p, labels=c("1/6", "1/3", "1/2", "2/3"))
str(bin.df)
-Michael
--
Michael Friendly Email: friendly AT yorku DOT ca
Professor, Psychology Dept. & Chair, Quantitative Methods
York University Voice: 416 736-2100 x66249 Fax: 416 736-5814
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Toronto, ONT M3J 1P3 CANADA
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