Permalink
Cannot retrieve contributors at this time
# | |
# tail-signif.R, 16 Jul 16 | |
# Data from: | |
# | |
# Example from: | |
# Evidence-based Software Engineering: based on the publicly available data | |
# Derek M. Jones | |
# | |
# TAG example | |
source("ESEUR_config.r") | |
plot_layout(2, 1) | |
par(mar=c(5, 1, 4, 1)+0.1) | |
pal_col=rainbow(3) | |
norm_mean=4 | |
norm_sd=1 | |
xpoints=seq(0, norm_mean+norm_sd*4, by=0.01) | |
ypoints=dnorm(xpoints, mean=norm_mean, sd=norm_sd) | |
qn=qnorm(c(0.975, 0.95), 0, norm_sd) | |
max_y=max(ypoints) | |
# Two-tailed significance test | |
plot(xpoints, ypoints, type="l", col=pal_col[3], fg="grey", col.axis="grey", yaxt="n", | |
bty="n", yaxt="n", | |
xlab="Two-tailed", ylab="") | |
q=c(norm_mean-qn[1], norm_mean+qn[1]) | |
lines(c(q[1], q[1]), c(0, max_y), col=pal_col[1]) | |
lines(c(q[2], q[2]), c(0, max_y), col=pal_col[1]) | |
upper_y=subset(ypoints, xpoints <= norm_mean-qn[1]) | |
upper_x=subset(xpoints, xpoints <= norm_mean-qn[1]) | |
polygon(c(upper_x, norm_mean-qn[1], 0), c(upper_y, 0, 0), col=pal_col[2]) | |
upper_y=subset(ypoints, xpoints >= norm_mean+qn[1]) | |
upper_x=subset(xpoints, xpoints >= norm_mean+qn[1]) | |
polygon(c(upper_x, norm_mean+qn[1]), c(upper_y, 0), col=pal_col[2]) | |
text(norm_mean, max_y/1.5, "Fail to reject\nnull hypothesis", cex=1.4) | |
text(norm_mean-norm_sd*2.0, max_y/3, "Reject null\nhypothesis", pos=2, cex=1.4) | |
text(norm_mean+norm_sd*2.0, max_y/3, "Reject null\nhypothesis", pos=4, cex=1.4) | |
# One-tailed significance test | |
plot(xpoints, ypoints, type="l", col=pal_col[3], fg="grey", col.axis="grey", yaxt="n", | |
bty="n", yaxt="n", | |
xlab="One-tailed", ylab="") | |
q=norm_mean+qn[2] | |
lines(c(q[1], q[1]), c(0, max_y), col=pal_col[1]) | |
upper_y=subset(ypoints, xpoints >= norm_mean+qn[2]) | |
upper_x=subset(xpoints, xpoints >= norm_mean+qn[2]) | |
polygon(c(upper_x, norm_mean+qn[2]), c(upper_y, 0), col=pal_col[2]) | |
text(norm_mean-1.3, max_y/1.5, "Fail to reject null hypothesis", cex=1.4) | |
text(norm_mean+norm_sd*1.7, max_y/3, "Reject null\nhypothesis", pos=4, cex=1.4) | |