Lesson 7: Explore Many Variables
Third Qualitative Variable
library(ggplot2)
setwd('C:/Users/User/Desktop/LessonR/lesson4')
pf <- read.csv('pseudo_facebook.tsv', sep = '\t')
ggplot(aes(x = gender, y = age),
data = subset(pf, !is.na(gender))) + geom_boxplot() +
stat_summary(fun.y = mean, geom = 'point', shape = 4)

ggplot(aes(x = age, y = friend_count),
data = subset(pf, !is.na(gender))) +
geom_line(aes(color = gender), stat = 'summary', fun.y = median)

library(dplyr)
##
## Attaching package: 'dplyr'
## The following objects are masked from 'package:stats':
##
## filter, lag
## The following objects are masked from 'package:base':
##
## intersect, setdiff, setequal, union
age_gender_group <- group_by(pf, age, gender)
age_gender_group <- filter(age_gender_group, !is.na(gender))
pf.fc_by_age_gender <- summarise(age_gender_group,
mean_friend_count = mean(friend_count),
median_friend_count = median(friend_count),
n = n())
arrange(pf.fc_by_age_gender, age)
## # A tibble: 202 x 5
## # Groups: age [101]
## age gender mean_friend_count median_friend_count n
## <int> <fctr> <dbl> <dbl> <int>
## 1 13 female 259.1606 148.0 193
## 2 13 male 102.1340 55.0 291
## 3 14 female 362.4286 224.0 847
## 4 14 male 164.1456 92.5 1078
## 5 15 female 538.6813 276.0 1139
## 6 15 male 200.6658 106.5 1478
## 7 16 female 519.5145 258.5 1238
## 8 16 male 239.6748 136.0 1848
## 9 17 female 538.9943 245.5 1236
## 10 17 male 236.4924 125.0 2045
## # ... with 192 more rows
head(pf.fc_by_age_gender, 10)
## # A tibble: 10 x 5
## # Groups: age [5]
## age gender mean_friend_count median_friend_count n
## <int> <fctr> <dbl> <dbl> <int>
## 1 13 female 259.1606 148.0 193
## 2 13 male 102.1340 55.0 291
## 3 14 female 362.4286 224.0 847
## 4 14 male 164.1456 92.5 1078
## 5 15 female 538.6813 276.0 1139
## 6 15 male 200.6658 106.5 1478
## 7 16 female 519.5145 258.5 1238
## 8 16 male 239.6748 136.0 1848
## 9 17 female 538.9943 245.5 1236
## 10 17 male 236.4924 125.0 2045
Plotting Conditional Summaries
ggplot(data = pf.fc_by_age_gender, aes(x = age, y = median_friend_count)) + geom_line(aes(color = gender), stat = 'summary', fun.y = median)

Reshaping Data
#install.packages('reshape2')
library(reshape2)
pf.fc_by_age_gender.wide <- dcast(pf.fc_by_age_gender,
age ~ gender,
value.var = 'median_friend_count')
head(pf.fc_by_age_gender.wide)
## age female male
## 1 13 148.0 55.0
## 2 14 224.0 92.5
## 3 15 276.0 106.5
## 4 16 258.5 136.0
## 5 17 245.5 125.0
## 6 18 243.0 122.0
### Alternative code with dplyr and tidyr
#library(dplyr)
#install.packages('tidyr')
#library(tidyr)
#pf.fc_by_age_gender.wide <- subset(pf.fc_by_age_gender[c('age', 'gender', 'median_friend_count')], !is.na(gender)) %>%
# spread(gender, median_friend_count) %>%
# mutate(ratio = male / female)
#head(pf.fc_by_age_gender.wide)
Ratio Plot
ggplot(data = pf.fc_by_age_gender.wide, aes(x = age, y = female / male)) +
geom_line() +
geom_hline(yintercept = 1, alpha = 0.3, linetype = 2)

Third Quantitative Variable
pf$year_joined <- floor(2014 - pf$tenure/365)
Cut a Variable
summary(pf$year_joined)
## Min. 1st Qu. Median Mean 3rd Qu. Max. NA's
## 2005 2012 2012 2012 2013 2014 2
table(pf$year_joined)
##
## 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
## 9 15 581 1507 4557 5448 9860 33366 43588 70
?cut
## starting httpd help server ...
## done
pf$year_joined.bucket <- cut(pf$year_joined, c(2004, 2009, 2011, 2012, 2014))
Plotting it All Together
table(pf$year_joined.bucket, useNA = 'ifany')
##
## (2004,2009] (2009,2011] (2011,2012] (2012,2014] <NA>
## 6669 15308 33366 43658 2
ggplot(data = subset(pf, !is.na(year_joined.bucket)), aes(x= age, y=friend_count)) +
geom_line(aes(color = year_joined.bucket), stat = 'summary', fun.y = median)

Plot the Grand Mean
ggplot(data = subset(pf, !is.na(year_joined.bucket)), aes(x= age, y=friend_count)) +
geom_line(aes(color = year_joined.bucket), stat = 'summary', fun.y = mean) +
geom_line(stat = 'summary', fun.y = mean, linetype = 2)

Friending Rate
with(subset(pf, tenure >= 1), summary(friend_count / tenure))
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 0.0000 0.0775 0.2205 0.6096 0.5658 417.0000
Friendships Initiated
ggplot(data = subset(pf, tenure >= 1), aes(x= tenure, y=friendships_initiated / tenure)) +
geom_line(aes(color = year_joined.bucket), stat = 'summary', fun.y = mean)

Bias-Variance Tradeoff Revisited
ggplot(aes(x = tenure, y = friendships_initiated / tenure),
data = subset(pf, tenure >= 1)) +
geom_line(aes(color = year_joined.bucket),
stat = 'summary',
fun.y = mean)

ggplot(aes(x = 7 * round(tenure / 7), y = friendships_initiated / tenure),
data = subset(pf, tenure > 0)) +
geom_smooth(aes(color = year_joined.bucket))
## `geom_smooth()` using method = 'gam'

ggplot(aes(x = 30 * round(tenure / 30), y = friendships_initiated / tenure),
data = subset(pf, tenure > 0)) +
geom_line(aes(color = year_joined.bucket),
stat = "summary",
fun.y = mean)

ggplot(aes(x = 90 * round(tenure / 90), y = friendships_initiated / tenure),
data = subset(pf, tenure > 0)) +
geom_line(aes(color = year_joined.bucket),
stat = "summary",
fun.y = mean)

Histograms Revisited
getwd()
## [1] "C:/Users/User/Desktop/LessonR/lesson5"
setwd("C:/Users/User/Desktop/LessonR/lesson5")
yo <- read.csv("yogurt.csv")
qplot(data = yo, x = price, fill = I('#F79420'))
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

Number of Purchases
summary(yo)
## obs id time strawberry
## Min. : 1.0 Min. :2100081 Min. : 9662 Min. : 0.0000
## 1st Qu.: 696.5 1st Qu.:2114348 1st Qu.: 9843 1st Qu.: 0.0000
## Median :1369.5 Median :2126532 Median :10045 Median : 0.0000
## Mean :1367.8 Mean :2128592 Mean :10050 Mean : 0.6492
## 3rd Qu.:2044.2 3rd Qu.:2141549 3rd Qu.:10255 3rd Qu.: 1.0000
## Max. :2743.0 Max. :2170639 Max. :10459 Max. :11.0000
## blueberry pina.colada plain mixed.berry
## Min. : 0.0000 Min. : 0.0000 Min. :0.0000 Min. :0.0000
## 1st Qu.: 0.0000 1st Qu.: 0.0000 1st Qu.:0.0000 1st Qu.:0.0000
## Median : 0.0000 Median : 0.0000 Median :0.0000 Median :0.0000
## Mean : 0.3571 Mean : 0.3584 Mean :0.2176 Mean :0.3887
## 3rd Qu.: 0.0000 3rd Qu.: 0.0000 3rd Qu.:0.0000 3rd Qu.:0.0000
## Max. :12.0000 Max. :10.0000 Max. :6.0000 Max. :8.0000
## price
## Min. :20.00
## 1st Qu.:50.00
## Median :65.04
## Mean :59.25
## 3rd Qu.:68.96
## Max. :68.96
unique(yo$price)
## [1] 58.96 65.04 48.96 68.96 39.04 24.96 50.00 45.04 33.04 44.00 33.36
## [12] 55.04 62.00 20.00 49.60 49.52 33.28 63.04 33.20 33.52
length(unique(yo$price))
## [1] 20
table(yo$price)
##
## 20 24.96 33.04 33.2 33.28 33.36 33.52 39.04 44 45.04 48.96 49.52
## 2 11 54 1 1 22 1 234 21 11 81 1
## 49.6 50 55.04 58.96 62 63.04 65.04 68.96
## 1 205 6 303 15 2 799 609
yo <- transform(yo, all.purchases = strawberry + blueberry +
pina.colada + plain + mixed.berry)
summary(yo$all.purchases)
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 1.000 1.000 2.000 1.971 2.000 21.000
### alternate verbose form
#yo$all.purchases <- yo$strawberry + yo$blueberry + yo$pina.colada + yo$plain + yo$mixed.berry
Prices over Time
qplot(x = all.purchases, data = yo, binwidth = 1,
fill = I('#099DD9'))

ggplot(data = yo, aes(x = time, y = price)) +
geom_jitter(alpha = 1/4, shape = 21, fill = I('#F79420'))

Looking at Samples of Households
set.seed(2056)
sample_id <- unique(yo$id)
sample.ids <- sample(x = sample_id, size = 16)
ggplot(aes(x = time, y = price),
data = subset(yo, id %in% sample.ids)) +
facet_wrap( ~ id) +
geom_line() +
geom_point(aes(size = all.purchases), pch = 1)

Scatterplot Matrix
#install.packages("GGally")
library(GGally)
##
## Attaching package: 'GGally'
## The following object is masked from 'package:dplyr':
##
## nasa
theme_set(theme_minimal(20))
# set the seed for reproducible results
set.seed(1836)
pf_subset <- pf[, c(2:15)]
names(pf_subset)
## [1] "age" "dob_day"
## [3] "dob_year" "dob_month"
## [5] "gender" "tenure"
## [7] "friend_count" "friendships_initiated"
## [9] "likes" "likes_received"
## [11] "mobile_likes" "mobile_likes_received"
## [13] "www_likes" "www_likes_received"
ggpairs(pf_subset[sample.int(nrow(pf_subset), 1000), ])
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

Heat Maps
nci <- read.table("nci.tsv")
colnames(nci) <- c(1:64)
nci.long.samp <- melt(as.matrix(nci[1:200,]))
names(nci.long.samp) <- c("gene", "case", "value")
head(nci.long.samp)
## gene case value
## 1 1 1 0.300
## 2 2 1 1.180
## 3 3 1 0.550
## 4 4 1 1.140
## 5 5 1 -0.265
## 6 6 1 -0.070
ggplot(aes(y = gene, x = case, fill = value),
data = nci.long.samp) +
geom_tile() +
scale_fill_gradientn(colours = colorRampPalette(c("blue", "red"))(100))
