Question

The data

You have been given data from red maple and white oak trees from a national forest dominated by mixed hardwood stands.  The following variables for each tree are included

Variable	Description
treecode	Tree label
location	Eastern or western location in the forest
Species	Species codes (MR= red maple, OW=white oak)
Dbh	Diameter at breast height (1.3 m) in cm
Height	Height in m

treecode,location,species,dbh,height
1-W-7,eastern,MR,46.8,39.2
1-N-1,eastern,MR,47.1,37.4
1-E-4,eastern,MR,60.6,41.1
2-M-2,eastern,MR,50.1,26.9
3-E-4,eastern,MR,16.4,25.2
3-M-6,eastern,MR,29.4,27.3
3-S-4,eastern,MR,33.3,38
3-N-5,eastern,MR,37.4,22.5
3-N-6,eastern,MR,36.4,25
4-M-3,eastern,MR,7.2,3.9
4-M-2,eastern,MR,8,6.1
5-E-3,eastern,MR,19.6,14.5
7-N-5,eastern,MR,41.6,34.1
8-W-5,eastern,MR,31.7,31
8-S-7,eastern,MR,39.4,31.2
11-M-3,eastern,MR,16.3,24.3
11-M-5,eastern,MR,22.8,26.2
11-M-8,eastern,MR,23.4,30.8
11-M-4,eastern,MR,29.5,25.6
11-N-7,eastern,MR,37.5,27.6
11-S-6,eastern,MR,40.4,34.8
13-M-3,eastern,MR,31.8,27.7
13-M-2,eastern,MR,67.4,37.8
14-M-5,eastern,MR,31.1,28.7
14-M-4,eastern,MR,35.4,30.6
14-W-2,eastern,MR,34.3,33.3
14-E-3,eastern,MR,41.5,32.4
14-N-3,eastern,MR,39.1,36.8
14-M-3,eastern,MR,51,43.4
42-N-1,western,MR,57.6,35.9
43-M-4,western,MR,2.5,4.8
43-M-5,western,MR,3.4,4.8
43-M-7,western,MR,7,7
43-M-9,western,MR,10.5,9.7
44-M-3,western,MR,18.2,22.3
44-E-3,western,MR,25.6,25.3
45-M-1,western,MR,62.7,40
46-M-1,western,MR,25.6,28.3
46-M-2,western,MR,28.7,26.6
46-M-5,western,MR,43.9,26.8
46-N-9,western,MR,50.9,36.1
46-M-7,western,MR,56.3,35.2
47-N-1,western,MR,8.6,8.7
47-E-4,western,MR,22.6,19.3
48-M-2,western,MR,26,21.6
48-S-5,western,MR,30.7,23.5
49-M-7,western,MR,38.3,26.8
49-W-1,western,MR,45.4,29.6
50-M-5,western,MR,27,19
3-W-5,eastern,OW,6,6.5
3-W-3,eastern,OW,12.5,7.8
3-M-4,eastern,OW,19.1,25.2
3-M-3,eastern,OW,34.4,25.2
7-M-3,eastern,OW,31.7,24.2
7-S-1,eastern,OW,40.2,23
7-N-6,eastern,OW,45.5,25.2
7-N-7,eastern,OW,52.4,31.3
7-W-5,eastern,OW,54.3,28.3
8-M-2,eastern,OW,37.8,30.9
8-E-1,eastern,OW,65,36.4
8-M-4,eastern,OW,68.1,32.2
9-S-6,eastern,OW,59.8,46.9
11-M-2,eastern,OW,12.1,18.6
11-E-2,eastern,OW,17.7,12.4
48-M-7,western,OW,62.5,27.6
49-M-8,western,OW,3.7,4.4
49-N-4,western,OW,47.8,19.5
49-M-6,western,OW,53.4,29.6
49-M-4,western,OW,56,25.3
49-M-3,western,OW,67.4,27.4
50-N-2,western,OW,45.4,20.8
50-M-7,western,OW,48.1,23.9
50-M-4,western,OW,45.4,23.4
50-M-2,western,OW,48.7,22.7
52-N-6,western,OW,5.2,7
53-E-2,western,OW,44.3,30.6
53-N-2,western,OW,45.3,23.7
53-M-5,western,OW,76.9,28.6
54-M-6,western,OW,32.7,23.3
54-M-2,western,OW,40.2,24.1
54-S-6,western,OW,47.8,26.1
55-M-1,western,OW,49,27
55-M-2,western,OW,66.3,26.7
56-M-3,western,OW,29.3,18.8
57-M-3,western,OW,37.9,37.4
58-M-6,western,OW,41.9,22.4
59-M-2,western,OW,24.7,15.1
61-M-6,western,OW,57.3,30.6
62-M-10,western,OW,4.1,8.3
62-M-2,western,OW,9.1,2.7

1. Read in the csv file into a dataframe called “trees” with either the Import utility in RStudio, or by using the function read.csv, e.g.:

trees = read.csv("C:/My Documents/ E-W MR-OW data.csv")

1. Examine the variables using the str function:

What kind of data is contained in the “species” variable?  What kind of data is contained in the height variable

2. Examine the first few lines of data using the head function:

head(trees)

Answer 1