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?

More passengers died than survived.

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

The largest group that did not survive are third class males.

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

The largest group of survivors was females from the first and second class.

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

A group that has more cases than expexted is male third class passengers that did not survive. If class and gender did not matter, then a lot more male passgengers from the third class would have survived.

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

A group with less cases than expected is males from the third class. If gender and class did not matter, then more males from the third class should have survived.

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 people had no improvement than those who improved.
2. The largest group that did not improve was those who got the placebo.
3. The largest group that did improve was those who were treated.
4. One group that has more cases than expected was the the people in the marked group that were treated.
5. A group with less cases than expected was those who had no improvement after being treated.

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.