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 survived?

No, more passengers died than survived.

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

The largest group that didn’t survive was 3rd class males.

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

The largest group that did survive was 1st class females.

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

More females in the 2nd class survived than expected.

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

Fewer females in the 2nd class died than what was 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.

1. No, more patients did not improve.
2. The largest group that didn’t improve were treated with the placebo.
3. The largest group that did improve received the actual treatment.
4. The patients that didn’t receive treatment and didn’t improve had more case than expected.
5. The patients that didn’t recieve treatment and showed marked improvement had fewer cases than expected.

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.