# growthcurve

0th

Percentile

##### Compare Groups of Growth Curves

Do all pairwise comparisons between groups of growth curves using a permutation test.

Keywords
regression
##### Usage
compareTwoGrowthCurves(group,y,nsim=100,fun=meanT)
##### Arguments
group
vector or factor indicating group membership. Missing values are allowed in compareGrowthCurves but not in compareTwoGrowthCurves.
y
matrix of response values with rows for individuals and columns for times. The number of rows must agree with the length of group. Missing values are allowed.
levels
a character vector containing the identifiers of the groups to be compared. By default all groups with two more more members will be compared.
nsim
number of permutations to estimated p-values.
fun
the statistic used to measure the distance between two groups of growth curves. Default to a mean t-statistic.
times
a numeric vector containing the column numbers on which the groups should be compared. By default all the columns are used.
verbose
should progress results be printed?
##### Details

compareTwoGrowthCurves performs a permutation test of the difference between two groups of growth curves. compareGrowthCurves does all pairwise comparisons between two or more groups of growth curves. Accurate p-values can be obtained by setting nsim to some large value, nsim=10000 say.

##### Value

• compareTwoGrowthCurves returns a list with two components, stat and p.value, containing the observed statistics and the estimated p-value. compareGrowthCurves returns a data frame with components
• Group1name of first group in a comparison
• Group2name of second group in a comparison
• Statobserved value of the statistic
• P.Valueestimated p-value

compareGrowthCurves(PlantGrowth$group,as.matrix(PlantGrowth$weight))