Nothing
see.ttest.tck <- function ()
{
old.par <- par(no.readonly = TRUE)
tclRequire("BWidget")
if (!exists("slider.env"))
slider.env <- NULL; suppressWarnings(rm(slider.env)); slider.env <<- new.env()# Dummy to trick R CMD check
mu1 <- -1
assign("mu1", tclVar(mu1), envir = slider.env)
mu2 <- 0
assign("mu2", tclVar(mu2), envir = slider.env)
sigma <- 1
assign("sigma", tclVar(sigma), envir = slider.env)
n <- 10
assign("n", tclVar(n), envir = slider.env)
alt <-tclVar("two.sided")
var.equal<-tclVar(0)
ylim <- c(0, dnorm(0, 0, 0.5))
norm.refresh <- function(...) {
dev.hold()
par(mfrow=c(2, 1))
mu1 <- as.numeric(evalq(tclvalue(mu1), envir = slider.env))
mu2 <- as.numeric(evalq(tclvalue(mu2), envir = slider.env))
sigma <- as.numeric(evalq(tclvalue(sigma), envir = slider.env))
n <- as.numeric(evalq(tclvalue(n), envir = slider.env))
alt <- tclvalue(alt)
ve <- as.logical(tclObj(var.equal))
y1 <- rnorm(n,mu1,sigma)
y2 <- rnorm(n,mu2,sigma)
if(alt == "two.sided")test <- "two"
if(alt == "less")test <- "lower"
if(alt == "greater")test <- "upper"
x <- rep(c("1","2","3"),each=n)
a <- t.test(y1, y2, alternative = alt, var.equal = ve)
t <- a$statistic
P <- a$p.value
nu <- as.numeric(a$parameter)
cols <- c(rgb(red=0.5,blue=0.6,green=0.5,alpha=.3), rgb(red=0.5,blue=0.5,green=0.6,alpha=.3))
rcols <- c(rep(rgb(red=0.5,blue=0.6,green=0.5),n), rep(rgb(red=0.5,blue=0.5,green=0.6),n))
curve(dnorm(x,mu1,sigma),from=-5,to=5,ylim=ylim,xlab=expression(italic(x)),ylab=expression(paste(italic(f),"(",italic(x),")", sep = "")))
mtext(side = 3, expression(paste(italic(t), "-test from random sample of populations:", sep = "")), line = -1.5)
mtext(side = 3, line = -2.5, bquote(paste("alternative = ", .(alt), " ", italic(t)," = ", .(round(t, 2)), " ",italic(P)," = ",.(round(P, 5)))))
xx <- seq(-10, 10, length = 500)
yy1 <- dnorm(xx, mu1, sigma)
yy2 <- dnorm(xx, mu2, sigma)
polygon(c(xx[xx <= 10], 10), c(yy1[xx <= 10], yy1[xx ==
-10]), col = cols[1])
polygon(c(xx[xx <= 10], 10), c(yy2[xx <= 10], yy2[xx ==
-10]), col = cols[2])
text(c(y1,y2),rep(0.008,n*2), c(rep(1,n),rep(2,n)), adj = c(0.5,0), cex = .9, col = rcols)
legend("topright", pch = 22, pt.cex = 1.7, pt.bg = cols,
legend = c(expression(italic(X)[1]), expression(italic(X)[2])),
bty = "n")
par(mar=c(4,4,0.5,2))
shade.t(t, nu=nu, tail= test)
dev.flush()
}
tclServiceMode(TRUE)
m <- tktoplevel()
tkwm.title(m, "Visualizing t-tests")
tkpack(tklabel(m, text = " Visualizing t-tests "))
tkwm.geometry(m, "+0+0")
tkpack(fr <- tkframe(m), side = "top")
tkpack(tklabel(fr, text = "\u03BC\u2081", font = c("Helvetica", "10",
"normal"), width = "10"), side = "right")
tkpack(sc <- tkscale(fr, command = norm.refresh, from = -4,
to = 4, orient = "horiz", resolution = 0.1, showvalue = TRUE),
side = "left")
assign("sc", sc, envir = slider.env)
evalq(tkconfigure(sc, variable = mu1), envir = slider.env)
tkpack(fr <- tkframe(m), side = "top")
tkpack(tklabel(fr, text = "\u03BC\u2082", font = c("Helvetica", "10",
"normal"), width = "10"), side = "right")
tkpack(sc <- tkscale(fr, command = norm.refresh, from = -4,
to = 4, orient = "horiz", resolution = 0.1, showvalue = TRUE),
side = "left")
assign("sc", sc, envir = slider.env)
evalq(tkconfigure(sc, variable = mu2), envir = slider.env)
tkpack(fr <- tkframe(m), side = "top")
tkpack(tklabel(fr, text = "\u03C3", font = c("Helvetica", "10",
"normal"), width = "10"), side = "right")
tkpack(sc <- tkscale(fr, command = norm.refresh, from = 0.1,
to = 2, orient = "horiz", resolution = 0.1, showvalue = TRUE),
side = "left")
assign("sc", sc, envir = slider.env)
evalq(tkconfigure(sc, variable = sigma), envir = slider.env)
tkpack(fr <- tkframe(m), side = "top")
tkpack(tklabel(fr, text = "n", font = c("Helvetica", "10",
"normal"), width = "10"), side = "right")
tkpack(sc <- tkscale(fr, command = norm.refresh, from = 2,
to = 20, orient = "horiz", resolution = 1, showvalue = TRUE),
side = "left")
assign("sc", sc, envir = slider.env)
evalq(tkconfigure(sc, variable = n), envir = slider.env)
alternative <- c("two.sided", "less", "greater")
comboBox1 <- tkwidget(m,"ComboBox", editable=FALSE, values=alternative, textvariable = alt, width = 10)
tkpack(tklabel(m, text = "Alternative"))
tkpack(comboBox1)
v.but <- tkcheckbutton(m, text="Variance equal", variable=var.equal)
tkpack(v.but)
tkpack(tkbutton(m, text = "Refresh", command = norm.refresh),
side = "left")
tkpack(tkbutton(m, text = "Exit", command = function() tkdestroy(m)),
side = "right")
on.exit(par(old.par))
}
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