On this R-data statistics page, you will find information about the cushny data set which pertains to Cushny and Peebles Prolongation of Sleep Data. The cushny data set is found in the robustbase R package. You can load the cushny data set in R by issuing the following command at the console data("cushny"). This will load the data into a variable called cushny. If R says the cushny data set is not found, you can try installing the package by issuing this command install.packages("robustbase") and then attempt to reload the data. If you need to download R, you can go to the R project website. You can download a CSV (comma separated values) version of the cushny R data set. The size of this file is about 341 bytes.

Cushny and Peebles Prolongation of Sleep Data

Description

The original data set was bivariate and recorded for ten subjects the prolongation of sleep caused by two different drugs. These data were used by Student as the first illustration of the paired t-test which only needs the differences of the two measurements. These differences are the values of cushny.

Usage

data(cushny)

Format

numeric vector, sorted increasingly:
0 0.8 1 1.2 1.3 1.3 1.4 1.8 2.4 4.6

Source

Cushny, A.R. and Peebles, A.R. (1905) The action of optical isomers. II. Hyoscines. J. Physiol. 32, 501–510.

These data were used by Student(1908) as the first illustration of the paired t-test, see also sleep; then cited by Fisher (1925) and thereforth copied in numerous books as an example of a normally distributed sample, see, e.g., Anderson (1958).

References

Student (1908) The probable error of a mean. Biometrika 6, 1–25.

Fisher, R.A. (1925) Statistical Methods for Research Workers; Oliver & Boyd, Edinburgh.

Anderson, T.W. (1958) An Introduction to Multivariate Statistical Analysis; Wiley, N.Y.

Hampel, F., Ronchetti, E., Rousseeuw, P. and Stahel, W. (1986) Robust Statistics: The Approach Based on Influence Functions; Wiley, N.Y.

Examples

data(cushny)plot(cushny,  rep(0, 10), pch = 3, cex = 3,
     ylab = "", yaxt = "n")
plot(jitter(cushny),  rep(0, 10), pch = 3, cex = 2,
     main = "'cushny' data (n= 10)", ylab = "", yaxt = "n")
abline(h=0, col="gray", lty=3)
myPt <- function(m, lwd = 2, ..., e = 1.5*par("cxy")[2])
  segments(m, +e, m, -e, lwd = lwd, ...)
myPt(  mean(cushny), col = "pink3")
myPt(median(cushny), col = "light blue")
legend("topright", c("mean", "median"), lwd = 2,
       col = c("pink3", "light blue"), inset = .01)## The 'sleep' data from the standard 'datasets' package:
d.sleep <- local({ gr <- with(datasets::sleep, split(extra, group))
                   gr[[2]] - gr[[1]] })
stopifnot(all.equal(cushny,
                    sort(d.sleep), tolerance=1e-15))

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Dataset imported from https://www.r-project.org.