Exercise Session 1
Justin Noel
10/27/2017
ISLR Exercise 8
Although we could use the ISLR package. We will download the dataset into our local directory.
download.file("http://www-bcf.usc.edu/~gareth/ISL/College.csv", "College.csv")Load our data frame from the file.
df <- read.csv("College.csv")Let’s look at it:
head(df)## X Private Apps Accept Enroll Top10perc
## 1 Abilene Christian University Yes 1660 1232 721 23
## 2 Adelphi University Yes 2186 1924 512 16
## 3 Adrian College Yes 1428 1097 336 22
## 4 Agnes Scott College Yes 417 349 137 60
## 5 Alaska Pacific University Yes 193 146 55 16
## 6 Albertson College Yes 587 479 158 38
## Top25perc F.Undergrad P.Undergrad Outstate Room.Board Books Personal PhD
## 1 52 2885 537 7440 3300 450 2200 70
## 2 29 2683 1227 12280 6450 750 1500 29
## 3 50 1036 99 11250 3750 400 1165 53
## 4 89 510 63 12960 5450 450 875 92
## 5 44 249 869 7560 4120 800 1500 76
## 6 62 678 41 13500 3335 500 675 67
## Terminal S.F.Ratio perc.alumni Expend Grad.Rate
## 1 78 18.1 12 7041 60
## 2 30 12.2 16 10527 56
## 3 66 12.9 30 8735 54
## 4 97 7.7 37 19016 59
## 5 72 11.9 2 10922 15
## 6 73 9.4 11 9727 55summary(df)## X Private Apps
## Abilene Christian University: 1 No :212 Min. : 81
## Adelphi University : 1 Yes:565 1st Qu.: 776
## Adrian College : 1 Median : 1558
## Agnes Scott College : 1 Mean : 3002
## Alaska Pacific University : 1 3rd Qu.: 3624
## Albertson College : 1 Max. :48094
## (Other) :771
## Accept Enroll Top10perc Top25perc
## Min. : 72 Min. : 35 Min. : 1.00 Min. : 9.0
## 1st Qu.: 604 1st Qu.: 242 1st Qu.:15.00 1st Qu.: 41.0
## Median : 1110 Median : 434 Median :23.00 Median : 54.0
## Mean : 2019 Mean : 780 Mean :27.56 Mean : 55.8
## 3rd Qu.: 2424 3rd Qu.: 902 3rd Qu.:35.00 3rd Qu.: 69.0
## Max. :26330 Max. :6392 Max. :96.00 Max. :100.0
##
## F.Undergrad P.Undergrad Outstate Room.Board
## Min. : 139 Min. : 1.0 Min. : 2340 Min. :1780
## 1st Qu.: 992 1st Qu.: 95.0 1st Qu.: 7320 1st Qu.:3597
## Median : 1707 Median : 353.0 Median : 9990 Median :4200
## Mean : 3700 Mean : 855.3 Mean :10441 Mean :4358
## 3rd Qu.: 4005 3rd Qu.: 967.0 3rd Qu.:12925 3rd Qu.:5050
## Max. :31643 Max. :21836.0 Max. :21700 Max. :8124
##
## Books Personal PhD Terminal
## Min. : 96.0 Min. : 250 Min. : 8.00 Min. : 24.0
## 1st Qu.: 470.0 1st Qu.: 850 1st Qu.: 62.00 1st Qu.: 71.0
## Median : 500.0 Median :1200 Median : 75.00 Median : 82.0
## Mean : 549.4 Mean :1341 Mean : 72.66 Mean : 79.7
## 3rd Qu.: 600.0 3rd Qu.:1700 3rd Qu.: 85.00 3rd Qu.: 92.0
## Max. :2340.0 Max. :6800 Max. :103.00 Max. :100.0
##
## S.F.Ratio perc.alumni Expend Grad.Rate
## Min. : 2.50 Min. : 0.00 Min. : 3186 Min. : 10.00
## 1st Qu.:11.50 1st Qu.:13.00 1st Qu.: 6751 1st Qu.: 53.00
## Median :13.60 Median :21.00 Median : 8377 Median : 65.00
## Mean :14.09 Mean :22.74 Mean : 9660 Mean : 65.46
## 3rd Qu.:16.50 3rd Qu.:31.00 3rd Qu.:10830 3rd Qu.: 78.00
## Max. :39.80 Max. :64.00 Max. :56233 Max. :118.00
## Uh oh. We can see that the college names have been converted into factors. This is not especially helpful. Let’s make these into the names of the rows.
rownames(df) <- df[,1]
head(df)## X Private Apps
## Abilene Christian University Abilene Christian University Yes 1660
## Adelphi University Adelphi University Yes 2186
## Adrian College Adrian College Yes 1428
## Agnes Scott College Agnes Scott College Yes 417
## Alaska Pacific University Alaska Pacific University Yes 193
## Albertson College Albertson College Yes 587
## Accept Enroll Top10perc Top25perc F.Undergrad
## Abilene Christian University 1232 721 23 52 2885
## Adelphi University 1924 512 16 29 2683
## Adrian College 1097 336 22 50 1036
## Agnes Scott College 349 137 60 89 510
## Alaska Pacific University 146 55 16 44 249
## Albertson College 479 158 38 62 678
## P.Undergrad Outstate Room.Board Books
## Abilene Christian University 537 7440 3300 450
## Adelphi University 1227 12280 6450 750
## Adrian College 99 11250 3750 400
## Agnes Scott College 63 12960 5450 450
## Alaska Pacific University 869 7560 4120 800
## Albertson College 41 13500 3335 500
## Personal PhD Terminal S.F.Ratio perc.alumni
## Abilene Christian University 2200 70 78 18.1 12
## Adelphi University 1500 29 30 12.2 16
## Adrian College 1165 53 66 12.9 30
## Agnes Scott College 875 92 97 7.7 37
## Alaska Pacific University 1500 76 72 11.9 2
## Albertson College 675 67 73 9.4 11
## Expend Grad.Rate
## Abilene Christian University 7041 60
## Adelphi University 10527 56
## Adrian College 8735 54
## Agnes Scott College 19016 59
## Alaska Pacific University 10922 15
## Albertson College 9727 55summary(df)## X Private Apps
## Abilene Christian University: 1 No :212 Min. : 81
## Adelphi University : 1 Yes:565 1st Qu.: 776
## Adrian College : 1 Median : 1558
## Agnes Scott College : 1 Mean : 3002
## Alaska Pacific University : 1 3rd Qu.: 3624
## Albertson College : 1 Max. :48094
## (Other) :771
## Accept Enroll Top10perc Top25perc
## Min. : 72 Min. : 35 Min. : 1.00 Min. : 9.0
## 1st Qu.: 604 1st Qu.: 242 1st Qu.:15.00 1st Qu.: 41.0
## Median : 1110 Median : 434 Median :23.00 Median : 54.0
## Mean : 2019 Mean : 780 Mean :27.56 Mean : 55.8
## 3rd Qu.: 2424 3rd Qu.: 902 3rd Qu.:35.00 3rd Qu.: 69.0
## Max. :26330 Max. :6392 Max. :96.00 Max. :100.0
##
## F.Undergrad P.Undergrad Outstate Room.Board
## Min. : 139 Min. : 1.0 Min. : 2340 Min. :1780
## 1st Qu.: 992 1st Qu.: 95.0 1st Qu.: 7320 1st Qu.:3597
## Median : 1707 Median : 353.0 Median : 9990 Median :4200
## Mean : 3700 Mean : 855.3 Mean :10441 Mean :4358
## 3rd Qu.: 4005 3rd Qu.: 967.0 3rd Qu.:12925 3rd Qu.:5050
## Max. :31643 Max. :21836.0 Max. :21700 Max. :8124
##
## Books Personal PhD Terminal
## Min. : 96.0 Min. : 250 Min. : 8.00 Min. : 24.0
## 1st Qu.: 470.0 1st Qu.: 850 1st Qu.: 62.00 1st Qu.: 71.0
## Median : 500.0 Median :1200 Median : 75.00 Median : 82.0
## Mean : 549.4 Mean :1341 Mean : 72.66 Mean : 79.7
## 3rd Qu.: 600.0 3rd Qu.:1700 3rd Qu.: 85.00 3rd Qu.: 92.0
## Max. :2340.0 Max. :6800 Max. :103.00 Max. :100.0
##
## S.F.Ratio perc.alumni Expend Grad.Rate
## Min. : 2.50 Min. : 0.00 Min. : 3186 Min. : 10.00
## 1st Qu.:11.50 1st Qu.:13.00 1st Qu.: 6751 1st Qu.: 53.00
## Median :13.60 Median :21.00 Median : 8377 Median : 65.00
## Mean :14.09 Mean :22.74 Mean : 9660 Mean : 65.46
## 3rd Qu.:16.50 3rd Qu.:31.00 3rd Qu.:10830 3rd Qu.: 78.00
## Max. :39.80 Max. :64.00 Max. :56233 Max. :118.00
## We are supposed to use the fix command. Let’s see what that is.
?fixOkay, that was not especially helpful. Let’s run it.
fix(df)I see. This gives me an incredibly ugly data frame editor.
Okay let’s get rid of the unneccessary column.
df <- df[,-1]Note that the “-1” here means that we will select all of the columns except the first one. This behavior is different from python where -1 will typically refer to the last column and -2 will refer to the second to last column.
Let’s see this in our ugly editor again.
fix(df)Okay, let’s look at our cleaned data frame:
summary(df)## Private Apps Accept Enroll Top10perc
## No :212 Min. : 81 Min. : 72 Min. : 35 Min. : 1.00
## Yes:565 1st Qu.: 776 1st Qu.: 604 1st Qu.: 242 1st Qu.:15.00
## Median : 1558 Median : 1110 Median : 434 Median :23.00
## Mean : 3002 Mean : 2019 Mean : 780 Mean :27.56
## 3rd Qu.: 3624 3rd Qu.: 2424 3rd Qu.: 902 3rd Qu.:35.00
## Max. :48094 Max. :26330 Max. :6392 Max. :96.00
## Top25perc F.Undergrad P.Undergrad Outstate
## Min. : 9.0 Min. : 139 Min. : 1.0 Min. : 2340
## 1st Qu.: 41.0 1st Qu.: 992 1st Qu.: 95.0 1st Qu.: 7320
## Median : 54.0 Median : 1707 Median : 353.0 Median : 9990
## Mean : 55.8 Mean : 3700 Mean : 855.3 Mean :10441
## 3rd Qu.: 69.0 3rd Qu.: 4005 3rd Qu.: 967.0 3rd Qu.:12925
## Max. :100.0 Max. :31643 Max. :21836.0 Max. :21700
## Room.Board Books Personal PhD
## Min. :1780 Min. : 96.0 Min. : 250 Min. : 8.00
## 1st Qu.:3597 1st Qu.: 470.0 1st Qu.: 850 1st Qu.: 62.00
## Median :4200 Median : 500.0 Median :1200 Median : 75.00
## Mean :4358 Mean : 549.4 Mean :1341 Mean : 72.66
## 3rd Qu.:5050 3rd Qu.: 600.0 3rd Qu.:1700 3rd Qu.: 85.00
## Max. :8124 Max. :2340.0 Max. :6800 Max. :103.00
## Terminal S.F.Ratio perc.alumni Expend
## Min. : 24.0 Min. : 2.50 Min. : 0.00 Min. : 3186
## 1st Qu.: 71.0 1st Qu.:11.50 1st Qu.:13.00 1st Qu.: 6751
## Median : 82.0 Median :13.60 Median :21.00 Median : 8377
## Mean : 79.7 Mean :14.09 Mean :22.74 Mean : 9660
## 3rd Qu.: 92.0 3rd Qu.:16.50 3rd Qu.:31.00 3rd Qu.:10830
## Max. :100.0 Max. :39.80 Max. :64.00 Max. :56233
## Grad.Rate
## Min. : 10.00
## 1st Qu.: 53.00
## Median : 65.00
## Mean : 65.46
## 3rd Qu.: 78.00
## Max. :118.00Good, the unnecessary factor data is gone and apparently some school has an awful graduation rate.
Which one is it?
which.min(df$Grad.Rate)## [1] 586Who is this culprit:
df[586,]## Private Apps Accept Enroll Top10perc Top25perc
## Texas Southern University No 4345 3245 2604 15 85
## F.Undergrad P.Undergrad Outstate Room.Board
## Texas Southern University 5584 3101 7860 3360
## Books Personal PhD Terminal S.F.Ratio
## Texas Southern University 600 1700 65 75 18.2
## perc.alumni Expend Grad.Rate
## Texas Southern University 21 3605 10Wow, we should avoid Texas Southern University.
Now, let us look at a pairwise scatterplot of the first ten columns.
pairs(df[,1:10])
That was ugly. Let’s try this again.
library(GGally)
ggpairs(df[,1:10])