This is my first R markdown homework.

1. Data Description:

The response is the length of odontoblasts (cells responsible for tooth growth) in 60 guinea pigs. Each animal received one of three dose levels of vitamin C (0.5, 1, and 2 mg/day) by one of two delivery methods, orange juice or ascorbic acid (a form of vitamin C and coded as VC). The dataset used for this homework is ToothGrowth from packagedatasets.

data("ToothGrowth", package = "datasets")
This data has 60 rows and 3 columns. So, the dimension is 60, 3. This is where I put inline code.

The three variables are:

  • len: Tooth Length
  • supp: Either OJ or VC
  • dose: Dose of Vitamin C

2. Checking dataset.

The code below lists the first 5 observation of the data.

head(ToothGrowth)
##    len supp dose
## 1  4.2   VC  0.5
## 2 11.5   VC  0.5
## 3  7.3   VC  0.5
## 4  5.8   VC  0.5
## 5  6.4   VC  0.5
## 6 10.0   VC  0.5

3. Summary statistics of the three variables of the data.

summary(ToothGrowth)
##       len        supp         dose      
##  Min.   : 4.20   OJ:30   Min.   :0.500  
##  1st Qu.:13.07   VC:30   1st Qu.:0.500  
##  Median :19.25           Median :1.000  
##  Mean   :18.81           Mean   :1.167  
##  3rd Qu.:25.27           3rd Qu.:2.000  
##  Max.   :33.90           Max.   :2.000

The mean length is 18.8133333 and the mean dose is 1.1666667. The two supp categories are OJ & VC.

4. Simple boxplot of the data.

boxplot(len~supp*dose, data=ToothGrowth, col=(c("red", "green")), main= "Box Plot of Tooth Growth" , xlab="Doses by Supplement", ylab="Tooth Growth")