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 Are more passengers survived?

No, more passengers died.

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

It was the 3rd class male that had the lowest survival rate.

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

First class female was the largest surviving group.

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

The 3rd class male ave more cases than expected, therefore didn’t survive.

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

3rd class males are least likely to survive.

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. More didn’t improve.
2. The placebos didn’t improve.
3. Patients that received the treatment.
4. The ones that were treated therefore more likely to show marked improvement.
5. The ones given placebos and showed marked improvement.

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.