Description Usage Arguments Value References Examples
This function conducts the test of no contract effect of treatments based on Theorem 3.2 of Wang, Higgins, and Blasi (2010).
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data |
The data in long format (see the example in function dataformat_wide_to_long( )). |
a |
The number of treatments. |
b |
The number of time points or repeated measurements per subject. |
mn |
The vector of sample sizes in treatments. |
h |
The h value used in the estimators in Theorem 3.2 of Wang, Higgins, and Blasi (2010). The value of h should be in (0, 0.5). Recommend to use the default value h=0.45 as given in the function. Note: If multiple values are provided to h as a vector, then the calculation will be carried out for each h value, which results in multiple p-values in the returned result. |
method |
Specifying method='rank' to use rank test. For all other values, the test based on original data will be used. |
Ca |
Contrast matrix for the contrast effect of the treatments. The default contrast corresponds to the main treatment effect. |
a matrix that contains the test statistics and pvalues for each h value.
Haiyan Wang and Michael Akritas (2010a). Inference from heteroscedastic functional data, Journal of Nonparametric Statistics. 22:2, 149-168. DOI: 10.1080/10485250903171621
Haiyan Wang and Michael Akritas (2010b). Rank test for heteroscedastic functional data. Journal of Multivariate Analysis. 101: 1791-1805. https://doi.org/10.1016/j.jmva.2010.03.012
Haiyan Wang, James Higgins, and Dale Blasi (2010). Distribution-Free Tests For No Effect Of Treatment In Heteroscedastic Functional Data Under Both Weak And Long Range Dependence. Statistics and Probability Letters. 80: 390-402. Doi:10.1016/j.spl.2009.11.016
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 | # Generate a data set that contains data from 3 treatments,
# with 3 subjects in treatment 1, 3 subjects in treatment 2,
# and 4 subjects in treatment 3. Each subject contains m=50
# repeated observations from Poisson distribution. For the 1st treatment,
# the mean vector of the repeated observations from the same subject is
# equal to mu1 plus a random effect vector generated by NorRanGen( ).
# The m is the number of repeated measurements per subject.
f1<-function(m, mu1, raneff) {
currentmu=mu1+raneff;
currentmu[abs(currentmu)<1e-2]=1e-2;
rpois(m, abs(currentmu))}
f2<-function(m, mu2, raneff) {
currentmu=mu2+raneff;
currentmu[abs(currentmu)<1e-2]=1e-2;
rpois(m, abs(currentmu))}
f3<- function(m, mu3, raneff){
currentmu=mu3+raneff;
currentmu[abs(currentmu)<1e-2]=1e-2;
rpois(m, abs(currentmu))}
# The a is the number of treatments. The mn stores the number of subjects in treatments.
a=3; mn=c(3, 3, 4); mu1=3; mu2=3; mu3=2; m=50
# Note treatment 3 has mean mu3=2, which is different from the mean of
# the other two treatments.
# Generate the time effects via random effects with AR(1) structure.
raneff=NorRanGen(m)
# Generate data and store in wide format.
datawide=numeric()
now=0
for (i in 1:a){
fi=function(x1, x2) f1(m,x1, x2)*(i==1)+f2(m,x1, x2)*(i==2)+f3(m, x1, x2)*(i==3)
mu=mu1*(i==1)+mu2*(i==2)+mu3*(i==3)
for (k in 1:mn[i]){
now=now+1
datawide<-rbind(datawide, c(k, i, fi(mu, raneff) ) )
colnames(datawide)=c("sub", "trt", paste("time", seq(m), sep=""))
#this is a typical way to store data in practice
}
} #end of j
# Note:There are different time effects since values in raneff vector are different
dat=dataformat_wide_to_long(datawide) #dat is in long format
#Note: For each h value below, the test statistic and p-value are calculated.
# (see Theorem 3.2 of Wang, Higgins, and Blasi (2010))
tcontrast(dat, a, m, mn, h=c(0.45, 0.49), method='original')
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