Problem 1

Before finishing and turning in any project, or sharing a project, it is recommended that you run this:

A. Code Code
B. Spell Check
C. Console editor
D. ? function

Problem 2

Which one of these R chunk options dictates whether the code that produces the result should be printed before the corresponding R output:

A. eval
B. include
C. echo
D. na.rm

Problem 3

Which of the following is one way to correctly extract and list the police_force_size data from the police_resid2 data frame:

A. police_resid2 + extract "police_force_size"
B. data = police_resid2, list = police_force size
C. police_resid2$police_force_size
D. police_resid2$c(police_force_size)

Problem 4

What would be the most appropriate plot for a situation that was attempting to plot the number of text messages sent daily by gender?

A. Histogram
B. Scatterplot
C. Barplot
D. Boxplot

Problem 5

What R chunk would produce a faceted histogram that plots age by orientation, with a binwidth of 10, and with each orientation a different color?

ggplot(data = profiles, mapping = aes(x = age)) + 
  geom_histogram(binwidth = 10, aes(fill = orientation)) +
  facet_wrap(~ orientation)

ggplot(data = okcupiddata, mapping = aes(x = age)) +
  geom_histogram(binwidth = 10, fill = orientation) +
  facet_wrap(~ orientation)

ggplot(data = profiles, mapping = aes(x = age)) +
  geom_histogram(bins = 10, aes(fill = "orientation")) +
  facet_wrap(~ orientation)

ggplot(data = okcupiddata, mapping = aes(x = age)) +
  geom_bar(binwidth = 10, fill = orientation) +
  facet_wrap(~ orientation)

Problem 6

You are asked to produce an appropriate plot for looking at the relationship between age and height. What kind of plot do you make?

A. Histogram
B. Scatterplot
C. Boxplot
D. Linegraph

Problem 7

What makes a data set tidy?

A. Each variable forms a column.
B. Each observation forms a row.
C. Each type of observational unit forms a table.
D. All of the above.

Problem 8

A boxplot is used for…

A. Two numerical variables.
B. Two categorical variables.
C. A numerical predictor and a categorical response.
D. A categorical predictor and a numerical response.

Problem 9

What is faceting?

A. It converts data units to physical units.
B. It creates small multiples of the same plot over a different numerical variable.
C. It creates small multiples of the same plot over a different categorical variable.
D. It dictates whether the code that produces the result should be printed before the corresponding R output.

Problem 10

Which of the following does aes()thetic NOT affect?

A. X/Y position
B. Depth
C. Color
D. Size

Problem 11

What is an appropriate graph to use when plotting a graph for two categorical variables?

A. Boxplot
B. Scatter plot
C. Histogram
D. Barplot

Problem 12

What is the most appropriate code for determining the relationship between sex and age?

ggplot(data = profiles, mapping = aes(x = sex, y = age)) +
  geom_boxplot()

ggplot(data = profiles, mapping = aes(x = sex, fill = name)) +
  geom_bar()

ggplot(data = profiles, mapping = aes(x = age, fill = sex)) +
  geom_bar()

ggplot(data = profiles, mapping = aes(x = age, y = sex)) +
  geom_boxplot()

Problem 13

Why should scatterplots be jittered or points transparent?

A. For beauty reasons only
B. The data should only be jittered not also made transparent
C. Because it is easier to read by reducing overplotting
D. They shouldn’t

Problem 14

What graph should be used when dealing with one categorical variable?

A. Histogram
B. Scatterplot
C. Barplot
D. Boxplot

Problem 15

Which R chunk produces the most appropriate faceted barplot of carrier based on name?

ggplot(data = flights_namedports, mapping = aes(x = carrier, fill = name)) +
  geom_bar() +
  facet_grid(name ~ .)

ggplot(data = flights_namedports, mapping = aes(x = name, fill = carrier)) +
  geom_bar() +
  facet_grid(. ~ name)

ggplot(data = flights_namedports, mapping = aes(x = carrier, fill = name)) +
  geom_bar() +
  facet_grid(carrier ~ .)

ggplot(data = flights_namedports, mapping = aes(x = name, fill = carrier)) +
  geom_bar() +
  facet_grid(. ~ carrier)

Problem 16

What type of plot would be used for a categorical predictor and a numerical response?

A. faceted bar plot
B. scatter plot
C. box plot
D. histogram

Problem 17

Why do we use R?

A. R is free!
B. R is easily reproducible.
C. R is set up to be so difficult that no one will succeed.
D. A and B

Problem 18

Which of these codes is the most correct?

ggplot(data = profiles, mapping = aes(x = drugs))
  geom_bar(color = coral, fill = "green", na.rm = TRUE)

ggplot(data=profiles, mapping= aes(x=drugs)) +
  geom_bar(color= "coral", fill= "green", na.rm = FALSE)

ggplot(data = profiles, mapping = aes(x = drugs)) +
        geom_bar(color = "coral", fill = "green", na.rm = TRUE)

ggplot(mapping = (aes) x = drugs, data = profiles,) +
        geom_bar(color = "coral", fill = "green", na.rm = TRUE)

Problem 19

When producing a code for a scatterplot, do we use the fill function or the color function to change the color of the points?

A. You use both.
B. color
C. Neither, you cannot use any type of color on a scatter plot.
D. fill

Problem 20

Tidy data is…

A. When the data set is small.
B. When things are organized in a nice and neat manner.
C. When each variable forms a row, and the observational unity forms a column.
D. When each variable forms a column, and the observational unit forms a row, and each type of observational unit forms a table.

Problem 21

What is one difference between a histogram and a bar plot?

A. A histogram has bars that touch, a bar plot has bars that do not touch.
B. A histogram has bars that touch, a bar plot has bars that are a different color, but also touch.
C. A histogram has bars that do not touch, a bar plot has bars that do touch.
D. A histogram is a large collection of dots, a bar plot is a line.

Problem 22

The Code Editor/View Window is?

A. located at the bottom left corner.
B. serves as a place to view contents of files and objects in R.
C. your R sandbox.
D. all of the above.

Problem 23

If you would like to list many entries in a vector object, you can do so by?

A. entering ?c in the R console
B. using the View function
C. both A and B
D. none of the above

Problem 24

Rules for naming objects in R include?

A. R is case-sensitive.
B. object names cannot begin with a number.
C. objects cannot contain symbols that are native to R or are used for mathematics.
D. all of the above.

Problem 25

geom refers to?

A. the X and Y position on a plot.
B. smoothing and binning values.
C. a type of plot.
D. adjustments.

Problem 26

Box plots are best for?

A. one categorical variable.
B. one numerical predictor and one numerical response.
C. one categorical predictor and one numerical response.
D. one categorical predictor and one categorical response.

Problem 27

One categorical variable is best displayed in which type of plot?

A. Histogram
B. Bar plot
C. Faceted bar plot
D. none of the above

Problem 28

What are the values given in a 5-number Summary?

A. Minimum, First Quartile, Mean, 3rd Quartile, Maximum
B. Low Outliers, First Quartile, Median, Third Quartile, High Outliers
C. Minimum, First Quartile, Median, Third Quartile, Maximum
D. First Quartile, Median, Third Quartile, Interquartile Range, Outliers

Problem 29

Which chunk produces the following graph with warning output?

## Warning: Removed 9430 rows containing non-finite values (stat_bin).

ggplot(data = flights, mapping = aes(x = arr_delay)) +
  geom_histogram(bins = 1000, color = "black", fill = "gold")

ggplot(data = flights, mapping = aes(x = arr_delay)) +
  geom_bar(binwidth = 15, color = "black", fill = "gold")

ggplot(data = flights, mapping = aes(x = arr_delay, fill = gold)) + 
  geom_histogram(bins = 10, color = "black")

ggplot(data = flights, mapping=aes(x = arr_delay)) +
  geom_histogram(binwidth = 100, color = black, fill = gold)

Problem 30

What are the correct definitions of the echo, eval, and include chunk options?

A. echo specifies whether the code AND its output should be in the resulting knitted document, eval specifies whether the code should be assessed or just displayed without its output, include dictates whether the code that produces the result should be printed before the corresponding R output.
B. echo specifies whether the code should be assessed or just displayed without its output, eval dictates whether the code that produces the result should be printed before the corresponding R output, include specifies whether the code AND its output should be in the resulting knitted document.
C. echo dictates whether the code that produces the result should be printed before the corresponding R output, eval specifies whether the code AND its output should be in the resulting knitted document, include specifies whether the code should be assessed or just displayed without its output.
D. echo dictates whether the code that produces the result should be printed before the corresponding R output, eval specifies whether the code should be assessed or just displayed without its output, include specifies whether the code AND its output should be in the resulting knitted document.

Problem 31

Given the flights data set, what plot would be most appropriate for comparing the variables carrier and arr_delay?

A. Faceted Barplot
B. Scatterplot
C. Boxplot
D. Faceted Histogram

Problem 32

What is NOT a feature of Tidy Data?

A. Rows correspond to observations
B. Data converted to Tidy data will be in Wide Format
C. Data converted to Tidy data will be in Long Format
D. Both A and B

Problem 33

What is not a reason we use R?

A. R only costs a few dollars to use
B. R is reproducible
C. R helps you find answers quickly
D. R makes it easy to collaborate

Problem 34

What is not the name of a type of graph?

A. Box plot
B. Flat plot
C. Histogram
D. Bar plot

Problem 35

Which one is not a panel seen on RStudio?

A. Checker
B. History
C. Console
D. Environment

Problem 36

What is not a key element of tidy data?

A. variables
B. values
C. observational unit
D. graph

Problem 37

What is not a component of Hadley Wickham’s workflow graphic?

A. Untidy
B. Import
C. Communicate
D. Understand

Problem 38

Which one of the following is a valid R code for a faceted plot?

A. facet_grid()
B. Facets()
C. facet_wrap()
D. A and C

Problem 39

What plot would correspond to a data set that compares one continuous numerical variable to one categorical variable?

A. Bar plot
B. Histogram
C. Scatter plot
D. Box plot

Problem 40

When usually would be a good reason to use a line graph over a scatter plot?

A. When you want to connect the dots to make a picture of a puppy
B. When the x-axis is time and each time point corresponds to one y value
C. If you are comparing a numerical variable to a categorical variable
D. If the scatter plot code you enter results in an error

Problem 41

What does it mean to “jitter” the points on a plot?

A. To shake the points a bit on the plot
B. To remove some of the over-plotting
C. To add “random noise” to the points to better see them
D. All of the above

Problem 42

What reason did Naomi Robbins, author of “Creating More Effective Graphs”, for why we shouldn’t use pie charts?

A. They do not look professional
B. We often overestimate angles greater than 90 degrees and we underestimate angles less than 90 degrees
C. Histograms are more efficient for categorical data and make it easier to analyze data
D. The word “pie” is a distraction from the data analysis

Problem 43

What are the main features of a tidy data set?

A. Observational units form columns and variables are in the rows
B. All variables are in one column and observational units are in the rows
C. A single variable forms a single column and all observations are in a row
D. Each observation is in a row and each single variable is a column

Problem 44

If you want to plot two variables, where the explanatory is categorical and the response is numeric, which types of graphs would be appropriate to use?

A. Faceted barplot & faceted histogram
B. Faceted histogram & line graph
C. Boxplot & faceted barplot
D. Boxplot & faceted histogram

Problem 45

If you want to plot two categorical variables which type of graph would be the most appropriate to use?

A. Boxplot
B. Bar plot
C. Faceted barplot
D. Faceted histogram

Problem 46

What is the difference between a faceted histogram and a faceted barplot?

A. A faceted histogram is used for two categorical variables and a faceted barplot is best for one categorical and one numeric variable
B. A faceted barplot is used for two categorical variables and a faceted histogram is used for a numeric explanatory variable and a categorical response variable
C. A faceted barplot shows two categorical variables and a faceted histogram shows two numeric variables
D. A faceted histogram is for plotting a categorical explanatory variable and a numeric response variable while a faceted barplot is for plotting a categorical explanatory and categorical response variable

Problem 47

What is one thing the factor function does?

A. Counts how many pieces of data there are for a given variable
B. Turns a continuous variable into a discrete variable
C. Turns a discrete variable into a categorical variable
D. Tells you what type of variable (categorical, numeric, integer) something is

Problem 48

Which of these would produce a side by side barplot of status faceted by sex with fill color determined by orientation?

ggplot(data = profiles, aes(status, fill = orientation)) +
  geom_bar() + 
  facet_wrap(~sex) + 
  (position = "dodge")

ggplot(data = profiles, aes(status, fill = orientation)) + 
  geom_bar(position = "dodge") + 
  facet_wrap(~sex)

ggplot(data = profiles, aes(status, fill = orientation)) + 
  geom_bar() + 
  facet_wrap(~sex)

ggplot(data = profiles, aes(status, fill = orientation)) +
  geom_bar(position = dodge) + 
  facet_wrap(~sex)

Problem 49

Which of these will give us rows 9 through 12 of the variable distance in the flights data set?

A. flights$distance[9:12]
B. flights$distance[-9:12]
C. flights$distance[c(9, 12)]
D. flights$distance [-c(8, 13)]

Problem 50

Which of these plots is not used when the explanatory variable is categorical?

A. Faceted barplot
B. Boxplot
C. Faceted histogram
D. Scatterplot

Problem 51

If you were to compare two variables such as percentage of voters by region, what plot would you use to display this distribution of data?

A. Barplot
B. Boxplot
C. Histogram
D. Scatterplot

Problem 52

What is the purpose of jittering when you have a large mass of points in a Scatterplot?

A. This function helps when there is a large mass of points because it makes the plot look nicer and saves you from confusion.
B. This function helps when there is a large mass of points because it allows you to shake the points a bit on the plot and fix overplotting.
C. This function helps when there is a large mass of points because it allows you to add just a bit of random noise to the points to better see them.
D. All of the above.

Problem 53

What 2 functions are most crucial when producing a faceted barplot?

A.factor and geom_bar functions
B.geom_bar and facet_grid functions
C.bins and facet_grid functions
D. None of the above.

Problem 54

Which of the following would be the result of running the following R code in the Console?

> library(okcupiddata)

A. R will load the okcupiddata package if the package is installed.
B. R will allow you to view the okcupiddata dataset.
C. It will allow you to remove the missing values in the okcupiddata dataset.
D. All of the above.

Problem 55

Why is the labs function useful in keeping your data distributions organized?

A.The labs function is useful because it allows you to label the x and y axis.
B.The labs function is useful because it allows you to change the default labels on the plot and add a title.
C.The labs function is useful because others are able to receive clarification of the data distribution, with the help of labels.
D. All of the above.

Problem 56

How are tidy datasets formed?

A. Variables in columns, observations in rows and values in the table.
B. Values in columns, variables in rows and observations in the table.
C. Observations in columns, values in rows and variables in the table.
D. None of the above.

Problem 57

If a dataset called class_examscore included 10 students names and grades that they received on three exams, how would you extract the first five student names in the dataset?

A. class_examscore$name[1:5]
B. class_examscore$name(c(1, 5))
C. class_examscore$name1:5
D. None of the above

Problem 58

A faceted barplot is most likely used when you are graphing….

A. Two categorical variables
B. Two numerical variables
C. One categorical variables
D. One numerical variables

Problem 59

To produce a histogram with 4 bins, fill color blue and border color green, what would the ending of the R chunk look like?

A. geom_histogram(bins = 4, color = "green", fill = "blue")
B. geom_histogram(bins = 4, color = green, fill = blue)
C. geom_histogram(bins = 4, color = "blue", fill = "green")
D. geom_histogram(bins = 4, color = blue, fill = green)

Problem 60

When would sometimes using the median be better and more reliable than using the mean?

A. The outliers won’t have a large impact on the median of values.
B. You should never use the median, always use the mean of the values.
C. The median may be a smaller value to the mean.
D. The median is easier to obtain.

Problem 61

Which code below corresponds to a histogram with 10 bins, a black outline, and a blue fill (assuming the appropriate call to ggplot with a + was made just before this)?

A. ggplot(binwidth = 10, color = "white", fill = "forestgreen")
B. geom_histogram(binwidth = 10, color = "black", fill = "blue")
C. geom_histogram(bins = 10, color = "black", fill = "blue")
D. geom_boxplot(binwidth = 10, color = "black", fill = "blue")

Problem 62

What is known as the five-number summary?

A. Minimum value, 1st quartile value, 2nd quartile value, 3rd quartile value, maximum value
B. The average of the first five numbers in the data set.
C. Minimum value, 1st quartile value, median, mean, 3rd quartile value
D. Minimum value, median, mean, maximum value, missing values

Problem 63

What is the biggest problem with pie charts compared to barplots?

A. Difficult to determine relative size of each piece because it is hard to judge angles.
B. Too many colors make it harder for someone to read the graph.
C. Uses percentages which is harder to analyze data with.
D. Pie charts are unable to weed out the unnecessary data points.

Problem 64

“Error: could not function 'ggplot'” appears in the R Console after running:

ggplot(data = alaska_flights, aes(x = dep_delay, y = arr_delay)) + 
   geom_point(alpha = 0.2)

What needs to be done to fix this error?

A. You need to put ggplot2 rather than ggplot in your code.
B. ggplot is a function in ggplot2, so you need to make sure ggplot2 is loaded via library(ggplot2) in a chunk above this chunk.
C. The g in ggplot needs to be capitalized: (Ggplot)
D. None of the above.

Problem 65

What does the following code do when it is run in R? (assuming that we have downloaded the police_resid2 data and loaded the ggplot2 package)?

ggplot(data = police_resid2, mapping = aes(x = white)) +
  geom_histogram(bins = 5, color = "white", fill = "red")

A. Displays a graph with 5 red colored bins
B. Creates a histogram on the white variable using the police_resid2 data
C. Highlights the border of the bars in the plot with white color
D. All the above

Problem 66

What does NOT make a dataset tidy?

A. Each variable forms a row.
B. Each variable forms a column.
C. Each type of observational unit forms a table.
D. Each observation forms a row.

Problem 67

Below are a few of the symbols and panes that are the most common within RStudio. Find the incorrect symbol or pane description.

A. The assignment operator is denoted by <- . You can read this as putting your contents of the left-hand-side into an object name whenever it appears in the right-hand-side.
B. The “History” tab allows you to store all of the codes in a file and then “run” that code whenever needed.
C. The “Viewer” tab shows the resulting HTML file created from the R Markdown “Knit.”
D. The “Plots” tab allows you to create graphs and/or figures without any code.

Problem 68

When would it be most appropriate to use a boxplot?

A. To compare the distribution of one or more quantitative variables across multiple levels of one categorical variable.
B. To compare and contrast the distribution of one quantitative variable across multiple levels of one categorical variable.
C. To contrast the distribution of one quantitative variable across multiple levels of one categorical variable.
D. To visualize the frequency of different categories of a categorical variable.

Problem 69

What can be done when missing values from a data set need to be excluded from analysis?

A. na.rm = TRUE
B. narm = FALSE
C. na = TRUE
D. na.rm = FALSE

Problem 70

Carefully analyze the code below:

if(!require("ggplot2"))
  install.packages("ggplot2", repos = "http://cran.rstudio.org")
library(ggplot2)
ggplot(data = weather, mapping = aes(x = temp))

If you wanted to produce a histogram, would the code above plot a histogram? Why or why not?

A. Yes. The code above specifically allows RStudio to plot the dataset.
B. No. The code just provided a backdrop. We need to be able to plot, thus we will follow up the code with a “+”. As seen in the code below.
```
ggplot(data = weather, mapping = aes(x = temp)) +
  geom_histogram()
```
C. Yes. The code above has provided the backdrop and added the layer needed to plot.
D. No. The code just provided a backdrop. We need to be able to plot, thus we will begin the following line with a “+”. As seen in the code below.
```
ggplot(data = weather, mapping = aes(x = temp)) 
  + geom_histogram()
```

Problem 71

Which plot is appropriate to plot the relationship between sex and education in the profiles okcupiddata data set?

A. Barplot
B. Faceted Barplot
C. Histogram
D. Faceted Histogram

Problem 72

Which code will correctly produce the appropriate plot (though it won’t be a really nice thing to look at…) to plot sex and education in the profiles okcupiddata data set?

ggplot(data = profiles, mapping = aes(x = education)) +
 geom_histogram(aes(fill = education), na.rm = TRUE)

ggplot(data = profiles, mapping = aes(x = education)) + 
  geom_bar(aes(fill = "education"), na.rm = TRUE) +
  facet_wrap(~sex)

ggplot(data = profiles, mapping = aes(x = education))+
 geom_bar(aes(fill = education), na.rm = TRUE) +
  facet_wrap(~ethnicity)

ggplot(data = profiles, mapping = aes(x = education)) +
  geom_bar(aes(fill = education), na.rm = TRUE) +
  facet_wrap(~sex)

Problem 73

What is the correct code to produce this graph?

ggplot(data = profiles, mapping = aes(x = smokes)) +
  geom_bar(aes(fill = smokes), na.rm = TRUE) +
  facet_wrap(~status)

ggplot(data = profiles, mapping = aes(y = smokes)) +
  geom_boxplot(aes(fill = smokes), na.rm = TRUE) +
  facet_wrap(~status)

ggplot(data = profiles, mapping = aes(x = smokes)) +
  geom_bar(aes(fill= "smokes"), na.rm = TRUE) +
  facet_wrap(~status)

ggplot(data = profiles, mapping = aes(x = status)) +
  geom_bar((aes(fill = smokes, na.rm = TRUE))) +
  facet_wrap(~smokes)

Problem 74

How does the placement of a ~ affect the display of the plot? For example, if it is facet_grid(. ~ size) compared to facet_grid(size ~ .)?

A. The placement of the ~ does not effect the plot display in this case.
B. The levels of size are displayed on the top of the graph with (. ~ size)
C. The levels of size are displayed on the right-hand-side of the graph (size ~)
D. Answers B and C

Problem 75

When a plot is skewed to the right it…?

A. Has large humps on the left
B. Has large humps on the right
C. Is bell shaped
D. None of the above

Problem 76

When using two categorical variables, what is the most appropriate plot to use?

A. Boxplot
B. Scatter-plot
C. Barplot
D. Faceted Bar

Problem 77

What precisely does the “box” of a boxplot represent?

A. 0th, 50th, and 100th percentiles
B. Below average, average, above average
C. 25th, 50th and 75th percentiles
D. Answers A and B

Problem 78

What is needed to make the following chunk of code correct?

ggplot(data = profiles, mapping = aes(x = drugs)) +
  geom_bar(color = "white", (fill = drugs), na.rm = TRUE)

A. (fill = "drugs")
B. , (na.rm = TRUE))
C. aes(fill = drugs)
D. None of the above

Problem 79

What is the c function used for?

A. Listing out entries and putting them into a vector object
B. Checking to see what type an object is
C. Categorizing different variables in a data set
D. Changing the color of histogram bins

Problem 80

How would we extract entries 2-34 from a variable of 72 entries?

A. [c(2-34)]
B. [c(2,34)]
C. [-c(2,34)]
D. [2:34]

Problem 81

Which of the following code is needed to produce a faceted histogram of age based on and colored by sex using the data set profiles from okcupiddata?

A. mapping = aes(x = age, fill = sex)
B. mapping = aes(x = sex, fill = age)
C. mapping = aes(x = age, y = sex)
D. mapping = aes(x = sex, y = age)

Problem 82

What type of graph is included in mapping two categorical variables?

A. Histogram
B. Barplot
C. Boxplot
D. Scatterplot

Problem 83

What function do I use to label/rename parts of a graph?

A. aes
B. ggplot
C. labs
D. wrap

Problem 84

What are the five named graphics (5NG)?

A. Histograms, Boxplots, Pie chart, Scatter plot, Line graph
B. Boxplot, Scatter plot, Line plot, Histogram, Barplot
C. Scatter plot, Histogram, Boxplot, Pie chart, Pictograph
D. None of the above

Problem 85

Which code is correct for producing a histogram with the rain variable with specified bins and color with no warning messages?

ggplot(data = weather, mapping = aes(x = rain)) +
  geom_histogram(binwidth = 10, fill = "limegreen", color = "black", na.rm = TRUE)

ggplot(data = weather, mapping = aes(x = rain, y = humid)) +
  geom_histogram(binwidth = 10, fill = "limegreen", color = "black", na.rm = TRUE)

ggplot(data = weather, mapping = aes(x = rain)) +
  geom_boxplot(binwidth = 10, fill = "limegreen", color = "black", na.rm = TRUE)

ggplot(data = weather, mapping = aes(x = rain)) +
  geom_histogram(fill = "limegreen", color = "black", na.rm = TRUE)

Problem 86

Which of the following is most appropriate for plotting the temperature in Oregon for the past month?

A. Box plot
B. Scatter plot
C. Faceted barplot
D. Histogram

Problem 87

What does skewed right mean when looking at a bar plot?

A. A majority of the data falls near the center of the graph
B. A majority of the data falls near the right side of the graph
C. A majority of the data falls near the left side of the graph
D. None of the above.

Problem 88

Which of the following is the best option for comparing the distributions of two variables that are not categorical?

A. You should never compare two variables
B. Histograms
C. Barplots
D. None of the above

Problem 89

How do you plot the relationship between age and height?

ggplot(data = profiles, mapping = sex, height) +
  geom_histogram()

ggplot(data = profiles, aes(x = age, y = height)) + 
  geom_bar()

ggplot(data = profiles, aes(x = age, y = height)) + 
  facet_histogram(na.rm = TRUE)

ggplot(data = profiles, aes(x= age, y= height)) + 
  geom_point(na.rm = TRUE)

Problem 90

Which of the following would be most appropriate when plotting one numerical and one categorical variable?

A. Box Plot
B. Histogram
C. Bar plot
D. Faceted histogram

Problem 91

Which chunk would create a faceted histogram of sex and age, with border color pink, and fill color based on the values of smokes, and 20 bins?

ggplot(data = profiles, mapping = (x = age, y = sex)) +
  geom_histogram(bins = 20, color = pink, fill = smokes)

ggplot(data = profiles, mapping = aes(x = age)) +
  geom_histogram(bins = 20, color = "pink", aes(fill = smokes)) +
  facet_grid(~sex)

ggplot(data = profiles, mapping = aes(x=age, y=sex)) +
         geom_histogram(bins = 20, color = pink, fill = "smokes")

ggplot(data=profiles, mapping=aes(x=age))+ 
  geom_histogram(bins=20, color = "pink", aes(fill = smokes)) + 
  facet_plot(sex)

Problem 92

Why do we wrap things in aes?

A. It reminds R that the values specified vary and aren’t fixed like a specific color.
B. Any specified color for fill or border needs to be wrapped in aes
C. All geometries must be wrapped to remind R that they plot values.
D. None of the above.

Problem 93

What is the biggest difference between a bar plot and a histogram?

A. Bar plot looks at 2 variables, histogram looks at 1
B. Histogram looks at 2 variables, bar plot looks at 1 variable
C. Histograms plot continuous variables, barplots plot categorical variables.
D. Histogram bars does not touch, barplot has continuous data and, thus, touching bars

Problem 94

What two types of variables do box plots compare?

A. Categorical, Numerical
B. Categorical, categorical
C. Numerical, Numerical
D. All of the above

Problem 95

What does the code look like for a histogram?

A. ggplot(data = , mapping = aes(x = )) + geom_histogram()
B. ggplot(data= , mapping = (x = )) + geom_histogram()
C. ggplot(data= , mapping = (aes=)) + geom_histogram ()
D. ggplot(data= , mapping = aes(x = )) + create_histogram()

Problem 96

What types of variables does a scatterplot graph?

A. categorical, categorical
B. categorical, numerical
C. numerical, numerical
D. none of the above

Problem 97

How do you set the transparency of points?

A. alpha =
B. trans =
C. add =
D. not possible

Problem 98

Why should you use a lineplot?

A. Great way to look at trends over time
B. You should never!
C. When you have a natural ordering to x and one corresponding value of y for each x value.
D. Both A and C

All practice problems for Quiz 2 on October 3

Due on Monday, October 3, 2016 at 10 AM PDT