One Minute Paper Results
What was the most important thing you learned during this class?
What important question remains unanswered for you?
Grammer of Graphics
Data Visualizations with ggplot2 
ggplot2is an R package that provides an alternative framework based upon Wilkinson’s (2005) Grammar of Graphics.ggplot2is, in general, more flexible for creating "prettier" and complex plots.Works by creating layers of different types of objects/geometries (i.e. bars, points, lines, polygons, etc.)
ggplot2has at least three ways of creating plots:qplotggplot(...) + geom_XXX(...) + ...ggplot(...) + layer(...)
We will focus only on the second.
Parts of a ggplot2 Statement
Data
ggplot(myDataFrame, aes(x=x, y=y))Layers
geom_point(),geom_histogram()Facets
facet_wrap(~ cut),facet_grid(~ cut)Scales
scale_y_log10()Other options
ggtitle('my title'),ylim(c(0, 10000)),xlab('x-axis label')
Lots of geoms
ls('package:ggplot2')[grep('^geom_', ls('package:ggplot2'))]## [1] "geom_abline" "geom_area" "geom_bar" ## [4] "geom_bin_2d" "geom_bin2d" "geom_blank" ## [7] "geom_boxplot" "geom_col" "geom_contour" ## [10] "geom_contour_filled" "geom_count" "geom_crossbar" ## [13] "geom_curve" "geom_density" "geom_density_2d" ## [16] "geom_density_2d_filled" "geom_density2d" "geom_density2d_filled" ## [19] "geom_dotplot" "geom_errorbar" "geom_errorbarh" ## [22] "geom_freqpoly" "geom_function" "geom_hex" ## [25] "geom_histogram" "geom_hline" "geom_jitter" ## [28] "geom_label" "geom_line" "geom_linerange" ## [31] "geom_map" "geom_path" "geom_point" ## [34] "geom_pointrange" "geom_polygon" "geom_qq" ## [37] "geom_qq_line" "geom_quantile" "geom_raster" ## [40] "geom_rect" "geom_ribbon" "geom_rug" ## [43] "geom_segment" "geom_sf" "geom_sf_label" ## [46] "geom_sf_text" "geom_smooth" "geom_spoke" ## [49] "geom_step" "geom_text" "geom_tile" ## [52] "geom_violin" "geom_vline"Data Visualization Cheat Sheet
Scatterplot
ggplot(legosets, aes(x=pieces, y=US_retailPrice)) + geom_point()
Scatterplot (cont.)
ggplot(legosets, aes(x=pieces, y=US_retailPrice, color=availability)) + geom_point()
Scatterplot (cont.)
ggplot(legosets, aes(x=pieces, y=US_retailPrice, size=minifigs, color=availability)) + geom_point()
Scatterplot (cont.)
ggplot(legosets, aes(x=pieces, y=US_retailPrice, size=minifigs)) + geom_point() + facet_wrap(~ availability)
Boxplots
ggplot(legosets, aes(x='Lego', y=US_retailPrice)) + geom_boxplot()
Boxplots (cont.)
ggplot(legosets, aes(x=availability, y=US_retailPrice)) + geom_boxplot()
Boxplot (cont.)
ggplot(legosets, aes(x=availability, y=US_retailPrice)) + geom_boxplot() + coord_flip()
Histograms
ggplot(legosets, aes(x = US_retailPrice)) + geom_histogram()
Histograms (cont.)
ggplot(legosets, aes(x = US_retailPrice)) + geom_histogram() + scale_x_log10()
Histograms (cont.)
ggplot(legosets, aes(x = US_retailPrice)) + geom_histogram() + facet_wrap(~ availability)
Density Plots
ggplot(legosets, aes(x = US_retailPrice, color = availability)) + geom_density()
ggplot2 aesthetics
Likert Scales 
Likert scales are a type of questionnaire where respondents are asked to rate items on scales usually ranging from four to seven levels (e.g. strongly disagree to strongly agree).
library(likert)library(reshape)data(pisaitems)items24 <- pisaitems[,substr(names(pisaitems), 1,5) == 'ST24Q']items24 <- rename(items24, c( ST24Q01="I read only if I have to.", ST24Q02="Reading is one of my favorite hobbies.", ST24Q03="I like talking about books with other people.", ST24Q04="I find it hard to finish books.", ST24Q05="I feel happy if I receive a book as a present.", ST24Q06="For me, reading is a waste of time.", ST24Q07="I enjoy going to a bookstore or a library.", ST24Q08="I read only to get information that I need.", ST24Q09="I cannot sit still and read for more than a few minutes.", ST24Q10="I like to express my opinions about books I have read.", ST24Q11="I like to exchange books with my friends."))likert R Package
l24 <- likert(items24)summary(l24)## Item low neutral## 10 I like to express my opinions about books I have read. 41.07516 0## 5 I feel happy if I receive a book as a present. 46.93475 0## 8 I read only to get information that I need. 50.39874 0## 7 I enjoy going to a bookstore or a library. 51.21231 0## 3 I like talking about books with other people. 54.99129 0## 11 I like to exchange books with my friends. 55.54115 0## 2 Reading is one of my favorite hobbies. 56.64470 0## 1 I read only if I have to. 58.72868 0## 4 I find it hard to finish books. 65.35125 0## 9 I cannot sit still and read for more than a few minutes. 76.24524 0## 6 For me, reading is a waste of time. 82.88729 0## high mean sd## 10 58.92484 2.604913 0.9009968## 5 53.06525 2.466751 0.9446590## 8 49.60126 2.484616 0.9089688## 7 48.78769 2.428508 0.9164136## 3 45.00871 2.328049 0.9090326## 11 44.45885 2.343193 0.9609234## 2 43.35530 2.344530 0.9277495## 1 41.27132 2.291811 0.9369023## 4 34.64875 2.178299 0.8991628## 9 23.75476 1.974736 0.8793028## 6 17.11271 1.810093 0.8611554likert Plots
plot(l24)
likert Plots
plot(l24, type='heat')
likert Plots
plot(l24, type='density')
Pie Charts
There is only one pie chart in OpenIntro Statistics (Diez, Barr, & Çetinkaya-Rundel, 2015, p. 48). Consider the following three pie charts that represent the preference of five different colors. Is there a difference between the three pie charts? This is probably a difficult to answer.
Pie Charts
There is only one pie chart in OpenIntro Statistics (Diez, Barr, & Çetinkaya-Rundel, 2015, p. 48). Consider the following three pie charts that represent the preference of five different colors. Is there a difference between the three pie charts? This is probably a difficult to answer.
