Calculates confidence interval for the mean or median of a distribution with unknown population variance
conf.interval(x, cl = 0.95, stat = "mean", std.error = TRUE)
lci Lower confidence interval value
uci Upper confidence interval value
mean If stat = "mean", mean value of distribution
mean Value of the mean or median
conf.level Confidence level used for confidence interval
std.error If std.error = TRUE standard error of distribution
Vector to calculate confidence interval for
Percent confidence level (default = 0.95)
Statistic (mean or median)
Return standard error (TRUE/FALSE)
Jeffrey S. Evans <jeffrey_evans@tnc.org>
x <- runif(100)
cr <- conf.interval(x, cl = 0.97)
print(cr)
d <- density(x)
plot(d, type="n", main = "PDF with mean and 0.97 confidence interval")
polygon(d, col="cyan3")
abline(v=mean(x, na.rm = TRUE), lty = 2)
segments( x0=cr[["lci"]], y0=mean(d$y), x1=cr[["uci"]],
y1=mean(d$y), lwd = 2.5,
col = "black")
legend("topright", legend = c("mean", "CI"),
lty = c(2,1), lwd = c(1,2.5))
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