This R Markdown details methods used in R to analyze data collected for my plant ecology lab at Smith College. I began by imputing data as usual:

rm(list=ls(all=TRUE))
BallGall <- read.csv("/Users/matthewhecking/Documents/Ball Gall Data 2.csv")
attach(BallGall)
head(BallGall)
##    PARASITE NPHight Npflowermass Phight Pflowermass BallGallWidth
## 1 ball gall     147         25.5    122        15.5          2.41
## 2 ball gall     122         26.5    132        15.5          2.65
## 3 ball gall     142         14.5    145        15.0          0.79
## 4 ball gall     135          6.3    137        16.0          1.01
## 5 ball gall     123          2.0     93         0.0          0.81
## 6 ball gall     126         10.0    112         0.0          2.43

The first command removed all data from the environment, ensuring that no values are confused with one another, and uploaded a revised data set.

names(BallGall)
## [1] "PARASITE"      "NPHight"       "Npflowermass"  "Phight"       
## [5] "Pflowermass"   "BallGallWidth"
mean(Phight)
## [1] 117.9649
sd(Phight)
## [1] 28.9778
sd(Phight)/57
## [1] 0.5083825

examples of how to generate mean, standard deviation, and standard error from the data set are shown above. This was done for each variable (excluding “PARASITE”)

Next, I wanted to graphically display the data, so I used the following commands to overlap data sets from different variables

plot(Pflowermass, col="blue", ylim=c(0,50), xlab="Plant Number", ylab="Flower Weight (g)", main="Average Flower Weight (Ball)")

par(new=TRUE)

plot(Npflowermass, col="red", ylim=c(0,50), xlab="", ylab="")

Make sure that the limits are equal when doing this.

Other graphs I made included best fit lines:

The best fit line command is as follows

fit = aov(lm(Phight ~ Pflowermass)) co <- coef(fit) abline(fit, lwd = 2, col=“blue”)

If you want to get the R squared values as well, you can use:

Pmodel = lm(Phight ~ Pflowermass)
summary(Pmodel)$r.squared
## [1] 0.26891
NPmodel = lm(NPHight ~ Npflowermass)
summary(NPmodel)$r.squared
## [1] 0.1154893

Here is another graph made using the same commands with different data:

## The following objects are masked from BallGall:
## 
##     NPHight, PARASITE, Pflowermass

## [1] 0.4040706
## [1] 0.4652524