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# Data Visualization with R Cognitive Class Answers

0 ## Get Certificate: Data Visualization with R

Module 1 – Basic Visualization Tools

Question 1:Choose the correct code from the following options to install the ggplot2 library in R.

• install.packages(ggplot2)
• install.package(“ggplot2”)
• install.packages(“ggplot2”)
• install.package(ggplot2)

Question 2:Select the correct code that provides numerical values to different segments of the pie chart?

• coord_polar(theta=’y’)
• coord_polar(‘y’)
• theta = coord_polar(‘y’)
• coord_polar()

Question 3: Select the correct code from the following options to remove the color of the bars in the histogram?

• xlab = 0
• alpha = I(0)
• binwidth = 0
• geom = 0

Module 2 – Basic Visualization Tools Continued

Question 1:Select the correct methods used to create a scatterplot in R?

• scatterplot3d()
• scatterplot()
• qplot()
• plot()
• All the above options are correct

Question 2:Select the correct parameter used to change the line width in a line graph using the geom_line() method ?

• line_size
• size
• line_width
• width

Question 3: Which parameter out of the following represents the Confidence Interval in Regression?

• confidence_interval
• se
• ci
• lm

Module 3 – Specialized Visualization Tools

Question 1:Select the correct option for the values of Median, Lower whisker, Upper whisker, First quartile, Third quartile for the dataset : 3, 5, 7, 8, 12, 13, 14, 18, 21?

• 33, 2, 5, 12, 18
• 6, 2, 22, 7, 2
• 12, 4, 2, 3, 17
• 12, 3, 21, 6, 16

Question 2:>> True or False : To create waffle charts in R, we use ggplot library which is used for graphs and also waffle library.

• True
• False

Question 3: When working with Radar Charts in R, what is the correct code used to suppress the warnings generated?

• (warn = -1)
• (warn = 1)
• options(warn = -1)
• None of the options are correct

Module 4 – How to create Maps

Question 1:Which function gives an object that represents an empty world map

• leaflet
• None of the options are correct

Question 2:What is the use of the method addTiles() in R?

• To divide map in tiles.
• To zoom in the map to see different countries and streets in detail.
• To create tiles view of map.
• All the options above are correct

Question 3: ___________ method is used to publish a tile layer on the map.

• leaf()
• leaflet()
• None of the above options are correct

Module 5 – How to build interactive web pages

Question 1:Which function is used to create the display of shiny app ?

• display()
• output functions
• fluidPage()
• input functions

Question 2:Which argument is used to position sliderbar on the right hand side in shiny app?

• align=”right”
• position=”right”
• position = “rightalign”
• sliderLayout(position=”right”)

Question 3: >>What does the ui.R file in R contain ?

• inputs for server.R
• layout and appearance of app.
• instructions to build output object.
• All the above options are correct

Final Exam Answers: Data Visualization with R

Question 1:Which of the following options indicate the features that make R suitable for Data Visualizations

• R is a free and open source tool
• Built for statistical computing
• Visualization Tools
• All the options above are correct

Question 2:if(“ggplot2” %in% rownames(installed.packages()) == FALSE) {install.packages(“ggplot2”)}library(ggplot2) Please select the correct explanation for the code from the following options

• Check if “ggplot2” library is already installed into R, if not then install it and load it into R environment
• Load the “ggplot2”library into R environment
• Install and load the “ggplot2” library into R environment
• Install the “ggplot2” library into R

Question 3: We want to create a Bar Graph with black filled bars, x and y axis labels as Cylinders and Number of cars respectively and outline color of bars as Red. Choose the correct code block from below which will create the desired graph.

• qplot(mtcars\$cyl, geom = “bar”, fill = I(“black”), xlab = “Cylinders”, ylab = “Number of Cars”, colour = I(“red”))
• qplot(mtcars\$cyl, geom = “histogram”, fill = I(“black”), xlab = “Cylinders”, ylab = “Number of Cars”, colour=I(“red”))
• qplot(mtcars\$cyl, fill = I(“black”), xlab = “Cylinders”, ylab=”Number of Cars”, outline=I(“red”)
• None of the options are correct

Question 4: Choose the correct parameter which will define the width of the bars in a Histogram.

• binwidth
• barWidth
• bar_width(value)
• width
• None of the options are correct

Question 5: A pie chart in ggplot2 is a transformed stacked bar plot. Select the correct function from the following options to convert a stacked bar plot into a pie chart?

• pieChart (theta=’y’)
• coord_polar(theta=’y’)
• transform(theta=’y’)
• None of the above options are correct

Question 6: Let’s assume we have the mtcars dataset and we want to create a Scatter Plot by using mpg and wt columns of this dataset. Select the correctcode from the options below which can create the plot for us with red colored points.

• ggplot(mtcars,aes(x=mpg,y=wt)) + geom_point()
• ggplot(mtcars,aes(x=mpg,y=wt)) + geom_point(shape=19, colour=”red”)
• ggplot(mtcars,aes(x=mpg,y=wt)) + geom_point(shape=19, “blue”)
• None of the options above are correct

Question 7: True or False: It is possible plot more than one line at a time in the same graph using the ggplot() method

• False
• True

Question 8: Choose the correct statement from the following options

• se parameter is used to display confidence interval
• There is no term Confidence Interval in Regression
• If you want to display confidence interval then either just ignore the se attribute, or set it to TRUE
• None of above options are correct

Question 9: Suppose we want to download a .csv file from the link below, https://ibm.box.com/shared/static/cmid70rpa7xe4ocitcga1bve7r0kqnia.csv and store it with name my_data.csv in “/resources/data/” folder. Select the correct code from the options below

• file(“https://ibm.box.com/shared/static/cmid70rpa7xe4ocitcga1bve7r0kqnia.csv”, “/resources/data/my_data.csv”)
• None of the options are correct

Question 10: Select the correct format from the following options to create a word cloud with a minimum frequency value 1 and maximum words 200?

• wordcloud(words = data, freq = frequency, min.freq = 1, max.words=200)
• wordcloud(data, frequency, minimun= 1, max.words=200)
• wordcloud(freq = frequency, min.freq = 1, maxWords=200)
• wordcloud(words = data, freq = frequency, min.freq = 1)

Question 11: Select the correct option to create a WordCloud that is centered?

• order = FALSE
• random.order = TRUE
• random.order = FALSE
• random = TRUE

Question 12: dplyr and Scales libraries in a Radar Chart are used for?

• filtering the dataset
• provides convenient viewing and utility functions
• pipe operations and to determine labels respectively
• None of the options are correct

Question 13: Which method is used to avoid displaying warnings, generated while Creating a Radar Chart?

• options(warns=-1)
• warns(-1)
• options(warn=-1)
• warnings(-1)

Question 14: ___________ can be used to adjust the size of Waffle Charts

• kernel
• IRkernel
• Ikernel
• None of the options are correct

Question 15: >> Which of the following parameters are used to create waffle charts in R?

• colors
• rows
• title
• xlab
• All the options above are correct

Question 16: Choose the correct method to create a Box Plot in R

• ggplot(df) + geom_boxplot()
• ggplot(df, aes(x=label, y=value))
• ggplot(df, aes(x=label, y=value)) + geom_boxplot()
• None of the options are correct

Question 17: What is the term used to indicate the difference between the first and third quartiles?

• lower whisker and upper whisker.
• first quartile
• third quartile
• Interquartile Range

Question 18: Which function gives an object that represents an empty world map

• leaflet
• All the options above are correct

Question 19: What is the use of the method addTiles() in R?

• To divide map in tiles.
• To zoom in the map to see different countries and streets in detail.
• To create tiles view of map.
• All the options above are correct

Question 20: Which function is used to create display of shiny app ?

• display()
• output functions
• fluidPage()
• input functions