Description Usage Format Source References Examples

Do female Platyfish prefer male Platyfish with yellow swordtails? A.L. Basolo proposed and tested a selection model in which females have a pre-existing bias for a male trait even before the males possess it. Six pairs of males were surgically given artificial, plastic swordtails—one pair received a bright yellow sword, the other a transparent sword. Females were given the opportunity to engage in courtship activity with either of the males. Of the total time spent by each female engaged in courtship during a 20 minute observation period, the percentages of time spent with the yellow-sword male were recorded.

1 |

A data frame with 84 observations on the following 3 variables.

`Proportion`

The proportion of courtship time spent by 84 females with the yellow-sword males

`Pair`

Factor variable with 6 levels—

`"Pair 1"`

,`"Pair 2"`

,`"Pair 3"`

,`"Pair 4"`

,`"Pair 5"`

and`"Pair 6"`

`Length`

Body size of the males

Ramsey, F.L. and Schafer, D.W. (2002). *The Statistical Sleuth: A
Course in Methods of Data Analysis (2nd ed)*, Duxbury.

Basolo, A.L. (1990). Female Preference Predates the Evolution of the
Sword in Swordtail Fish, *Science* **250**: 808–810.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | ```
str(case0602)
boxplot(Proportion~Pair, case0602, ylab="Proportion")
#as in Display 6.5
summary(aov(Proportion~Pair, case0602))
n.fish <- with(case0602, tapply(Proportion, Pair, length))
av.fish <- with(case0602, tapply(Proportion, Pair, mean))
sd.fish <- with(case0602, tapply(Proportion, Pair, sd))
male.body.size <- with(case0602, tapply(Length, Pair, unique))
mean.body <- mean(male.body.size)
table.fish <- data.frame(n.fish, round(av.fish*100,2),
round(sd.fish*100,2), male.body.size,
2*(male.body.size-mean.body))
names(table.fish) <- c("n", "average", "sd", "male.body.size", "coefficient")
s.pooled <- with(table.fish, round(sqrt(sum(sd^2*(n-1))/sum(n-1)),2))
g <- with(table.fish, sum(average*coefficient))
se.g <- with(table.fish, round(s.pooled*sqrt(sum(coefficient^2/n)),2))
g/se.g
``` |

Embedding an R snippet on your website

Add the following code to your website.

For more information on customizing the embed code, read Embedding Snippets.