# FootHead: Head measurements of football players In heplots: Visualizing Hypothesis Tests in Multivariate Linear Models

## Description

Data collected as part of a preliminary study examining the relation between football helmet design and neck injuries. There are 30 subjects in each of three groups: High school football players, college players and non-football players.

## Usage

 `1` ```data(FootHead) ```

## Format

A data frame with 90 observations on the following 7 variables.

`group`

a factor with levels `High school` `College` `Non-football`

`width`

a numeric vector: head width at widest dimension

`circum`

`front.back`

a numeric vector: front to back distance at eye level

`eye.top`

a numeric vector: eye to top of head

`ear.top`

a numeric vector:ear to top of head

`jaw`

a numeric vector: jaw width

## Source

Rencher, A. C. (1995), Methods of Multivariate Analysis, New York: Wiley, Table 8.3.

## Examples

 ``` 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``` ```data(FootHead) str(FootHead) require(car) # use Helmert contrasts for group contrasts(FootHead\$group) <- contr.helmert contrasts(FootHead\$group) foot.mod <- lm(cbind(width, circum,front.back,eye.top,ear.top,jaw)~group, data=FootHead) Manova(foot.mod) # show the HE plot for the first two variables heplot(foot.mod, main="HE plot for width and circumference", fill=TRUE, col=c("red", "blue")) # show it with tests of Helmert contrasts heplot(foot.mod, hypotheses=list("group.1"="group1","group.2"="group2"), col=c("red", "blue", "green3", "green3" ), main="HE plot with orthogonal Helmert contrasts") # show all pairwise HE plots pairs(foot.mod) # ... with tests of Helmert contrasts pairs(foot.mod, hypotheses=list("group.1"="group1","group.2"="group2"), col=c("red", "blue", "green3", "green3"), hyp.labels=FALSE) # see that the hypothesis for groups really is 2D if(requireNamespace("rgl")){ heplot3d(foot.mod, variables=c(1,2,6), hypotheses=list("group.1"="group1","group.2"="group2"), col=c("red", "blue", "green3", "green3" ), wire=FALSE) } ```

heplots documentation built on Oct. 7, 2021, 1:07 a.m.