IntroR.rmd

## Read in the iris dataset
```{r}
#This step is not necessary as "iris" is installed automatically in "R".
#iris2 <- read.csv("iris.csv",header=T)
```
##
```{r}
iris2 <- read.csv("iris.csv",header=T)
```
##
```{r}
#What are the iris data set column names?
colnames(iris)
```
##
```{r}
#Extract the first two rows of the irisset and print them.
iris[1:2,]
```
##
```{r}
#How many rows are in the irisset?
nrow(iris)
```
##
```{r}
#Extract the last two rows of the iris set and print them.
rows <- nrow(iris)
iris[(rows-1):rows,]
```
##
```{r}
#What is the iris value in the 47th row?
iris[47,1]
```
##
```{r}
#What is mean Solar.R value of subset with Ozone > 31 and Temp > 90?
mean(subset(iris, Ozone>31 & Temp > 90)[,2])
```
## Ozone 
```{r}
#What is the iris type of the Month column?
class(iris[,5])
```
## Ozone 
```{r}
#What is the mean of Temp when Month is 6?
mean(subset(iris, iris[,5]==6)[,4])
```
## Ozone 
```{r}
#How many missing values are in the Ozone column?
sum(!complete.cases(iris[,1]))
```
## Ozone 
```{r}
#What is the mean value of the Ozone column (excluding missing values)?
mean(iris[complete.cases(iris),1])
```