Mosaic Plot

In this exercise you will learn to visualize the pairwise relationships between a set of quantitative variables. To this end, you will make your own note of 8.5 Mosaic plots from Data Visualization with R.

Mosaic charts can display the relationship between categorical variables using:

• rectangles whose areas represent the proportion of cases for any given combination of levels, and
• the color of the tiles to indicate the degree relationship among the variables.

The Titanic data set came from https://osf.io/aupb4/.

In the graph below,

• dark blue represents more cases than expected given independence (by chance); and
• dark red represents less cases than expected if independence holds (by chance).

Q1 Did more passengers survive?

More people died than survived.

Q2 Describe the largest group that didn’t survive. Discuss by class and gender.

Third class males was the largest group to not survive.

Q3 Describe the largest group that did survive. Discuss by class and gender.

First class females were the largest group to survive.

Q4 Describe one group that has more cases than expected given independence (by chance). Discuss by class and gender.

There were more third class male passengers that had died than expected. There were more first and second class female passengers that survived than expected.

Q5 Describe one group that has less cases than expected given independence (by chance). Discuss by class and gender.

There were less first and second class females that died than expected. There was less second and third class males to survive than expected.

Q6 Create a mosaic plot for Arthritis in the same way as above.

Hint: The Arthritis data set is from the vcd package. Add an additional argument gp = shading_max in the mosaic function. This is because the residuals are too small to have color.

Q7 Repeat Q1-Q5.

Less people improved compared to how many did not improve.

The largest group that did not improve were treated with placebo.

The largest group that did improve received treatment.

The groups that received more cases than expected was the group that received placebo, but did not improve and the group that receive treatment and did improve.

The groups that received less cases than expected were treated, but had no improvement and the people who had placebo treatment, but did improve.

Q8 Hide the messages, the code and its results on the webpage.

Hint: Use message, echo and results in the chunk options. Refer to the RMarkdown Reference Guide.

Q9 Display the title and your name correctly at the top of the webpage.

Q10 Use the correct slug.