Problem Set 1

Directions

During ANLY 512 we will be studying the theory and practice of data visualization. We will be using R and the packages within R to assemble data and construct many different types of visualizations. We begin by studying some of the theoretical aspects of visualization. To do that we must appreciate the actual steps in the process of making a visualization.

Most of us use softare to do this and have done so for so long that we have lost an appreciation for the mechanistic steps involved in accurately graphing data. We will fix that this week by creating a series of analog (meaning you draw them by hand) graphics. The visualizations you create must be numerically and visually accurate and precisely scaled. Because of that the data sets we visualize will be small.

A couple of tips, remember that there is preprocessing involved in many graphics so you may have to do summaries or calculations to prepare, those should be included in your work.
To ensure accuracy pay close attention to axes and labels, you will be evaluated based on the accuracy of your graphics.

The final product of your homework (this file) should include scanned or photographed images for each question below and a short summary of the process.

To submit this homework you will create the document in Rstudio, using the knitr package (button included in Rstudio) and then submit the document to your Rpubs account. Once uploaded your will submit the link to that document on Moodle.

Questions

Find the mtcars data in R. This is the dataset that you will use to create your graphics. Use that data to draw by hand graphics for the next 4 questions.

Draw a pie chart showing the proportion of cars from the mtcars data set that have different carb values.

Count the number of cars of each different number of carburetors in the collected dataset. Then, calculate the proportion of each category against the total number of cars.

## 
##       1       2       3       4       6       8 
## 0.21875 0.31250 0.09375 0.31250 0.03125 0.03125

Draw a bar graph, that shows the number of each gear type in mtcars.

Count the number of cars of each ‘gear’ type and then determine the scale of bars for the graph.

## 
##  3  4  5 
## 15 12  5

Next show a stacked bar graph of the number of each gear type and how they are further divded out by cyl.

Draw a bar graph to show the number of cars of each gear type and then divide each bar by the proportion of cars with different number of cylinders for each gear type.

##    
##      3  4  5
##   4  1  8  2
##   6  2  4  1
##   8 12  0  2

Draw a scatter plot showing the relationship between wt and mpg.

Determine the scale of axes by the maximum and minimum value of ‘wt’ and ‘mpg’ and then find the intersection point of each pair of ‘wt’ and ‘mpg’ in the dataset.

Design a visualization of your choice using the data.

This plot is to show the number of cars by Cylinder and Transmission Type. First, count the number of cars of each cyclinder type and then divide them into two different transmission types.

##    
##      0  1
##   4  3  8
##   6  4  3
##   8 12  2

Problem Set 1

Visualization Process

Directions

Questions