Author: Romerl Elizes

Step 0 - Load Present Data

data(iris)

Questions for Student

  1. How many cases were included in the data?

Using the dim function, We find that there are 150 cases in iris data.

dim(iris)
## [1] 150   5
  1. How many numerical variables are included in the data? Indicate what they are, and if they are continuous or discrete.

Using head function to display the top 10 rows of iris data, there are 4 numerical variables: Sepal.Length, Sepal.Width, Petal.Length, and Petal.Width.

The definitions for continuous and discrete same vague to me. However, using the reference from a Georgia State School website (ref: http://www.henry.k12.ga.us/ugh/apstat/chapternotes/7supplement.html), all of the numerical variables of iris are continuous because they each need to be measured to arrive at lengths and widths.

head(iris,10)
##    Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## 1           5.1         3.5          1.4         0.2  setosa
## 2           4.9         3.0          1.4         0.2  setosa
## 3           4.7         3.2          1.3         0.2  setosa
## 4           4.6         3.1          1.5         0.2  setosa
## 5           5.0         3.6          1.4         0.2  setosa
## 6           5.4         3.9          1.7         0.4  setosa
## 7           4.6         3.4          1.4         0.3  setosa
## 8           5.0         3.4          1.5         0.2  setosa
## 9           4.4         2.9          1.4         0.2  setosa
## 10          4.9         3.1          1.5         0.1  setosa
  1. How many categorical variables are included in the data, and what are they? List the corresponding levels (categories).

Only 1 categorial variable exists: Species.

Using some R methods to obtain the unique values of species, we find that the levels are: setosa, versicolor, and virginica.

speciestable <- iris[,c(5)]
specieslevels <- unique(speciestable)
specieslevels
## [1] setosa     versicolor virginica 
## Levels: setosa versicolor virginica