Cox Stuart Trend Test
Performs the Cox Stuart test of randomness.
cox.stuart.test(x, alternative)
x |
a numeric vector containing the data |
alternative |
a character string with the alternative hypothesis. Must be one of " |
Missing values are removed.
Data is grouped in pairs with the ith observation of the first half paired with the ith observation of the second half of the time-ordered data. If the length of vector X is odd the middle observation is eliminated. The cox stuart test is then simply a sign test applied to these paired data.
The possible values "two.sided
", "left.sided
" and "right.sided
" define the alternative hypothesis.
By using the alternative "two.sided
" the null hypothesis of randomness is tested against either an upward trend or an downward trend. By using the alternative "left.sided
" the null hypothesis of randomness is tested against an upward trend. By using the alternative "right.sided
" the null hypothesis of randomness is tested against a downward trend.
A list with class "htest" containing the components:
statistic |
The number of pairs with a signal "+" |
n |
The number of pairs, after eliminanting ties. |
p.value |
the p-value for the test. |
alternative |
a character string describing the alternative hypothesis. |
method |
a character string indicating the test performed. |
data.name |
a character string giving the name of the data. |
Ayana Mateus
Conover, W.J. (1999). Practical Nonparametric Statistics, 3rd edition, John Wiley & Sons (p. 166).
Cox, D. R. and Stuart, A. (1955). Some quick sign test for trend in location and dispersion, Biometrika, 42, 80-95.
Sprent, P. and Smeeton, N.C. (2007). Applied Nonparametric Statistical Methods, 4th ed., Chapman and Hall/CRC Texts in Statistical Science (p. 108).
## ## Example 1 ## Conover (1999) ## The total annual precipitation recorded each year, for 19 years. ## precipitation <- c(45.25, 45.83, 41.77, 36.26, 45.37, 52.25, 35.37, 57.16, 35.37, 58.32, 41.05, 33.72, 45.73, 37.90, 41.72, 36.07, 49.83, 36.24, 39.90) cox.stuart.test(precipitation) ## ## Example 2 ## Sweet potato production, harvested in the United States, between 1868 and 1937. ## data(sweetpotato) cox.stuart.test(sweetpotato$production)
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