Usable Security and Privacy
Problem Set 4

Due in class, on paper at 3:00pm on Monday, May 1st.

Problem 1 (25 points)

A handful of papers you have read so far in this class have used statistics to support their arguments. In particular, for this problem, you should consider the following five papers: Woodruff et al. (April 3rd); Ur et al. (April 5th); Akhawe and Felt (April 12th); Johnson et al. (April 17th); and Felt et al. (April 24th).

Skim back through these five papers and note what different statistical tests they use. Then, create and submit a table that shows how these five studies used different statistical tests. Use the following format for your table, where each row represents an analysis you found in one of the papers:

• Column 1: Which paper? (e.g., Woodruff et al.)
• Column 2: What is the name of the statistical test they used? (e.g., ANOVA)
• Column 3: What is the question they're trying to investigate using statistics? (e.g., Is privacy concern correlated with age?)
• Column 4: What format is their data in? (e.g., survey responses rating agreement on a 7-point Likert scale. They binned these responses into two groups: "agree" and "not agree")
• Column 5: How did they report the results of the test in the paper? (e.g., [χ2=168.07, p<.001]
• Column 6: (If applicable) Do they make any interesting comments about why they chose this test? (e.g., The data are not normally distributed.) Similarly, note if they performed any kind of correction for multiple testing.

Group the rows of your table based on the type of analysis the statistics are being used to support. It may be easiest to split your table into multiple smaller tables. For example, if one paper uses statistical test Foo to compare Likert-scale survey questions and another paper uses statistical test Foo or statistical test Bar to compare survey questions where the structure of the data or comparison seems similar, group those together.

Note that even if a particular paper uses a particular test multiple times, you only need to report it once in your table. For example, if Ur et al. use the XYZ test 15 times and the ABC test 32 times, you only need to report once in your table that Ur et al. use the XYZ test (pick representative answers for each column of your table) and once that Ur et al. use the ABC test.

Problem 2 (25 points)

We have provided you the following dataset about deaths on the Titanic. The first link is to the raw data. The second explains the dataset; its appendix explains the column values.

1. The raw data
2. Robert J. MacG. Dawson. The "Unusual Episode" Data Revisited. Journal of Statistics Education v.3, n.3 (1995)

Using whatever tool you prefer, conduct two different (appropriate) statistical tests to analyze this data.

You should turn in a single paragraph containing all of the following information:

1. What were you analyzing?
2. What statistical test did you use, and how did you choose it?
3. What software did you use to analyze the data?
4. Give the result of the test (including p value).
5. Briefly interpret your result.

If you don't have prior experience with any statistical software, we highly recommend you go through Blase's R tutorial, which includes lots of sample code.

Problem 3 (25 points)

Political activists frequently fear being surveilled by a wide range of adversaries (ranging from governments to opposing factions), yet often lack the technical knowledge to keep themselves secure and private.

To help bridge this gap, create a 1-2 page overview for (non-technical) activists outlining what you believe to be the essential steps they can take to protect their privacy and security, including everything you think they need to know. We'd like to actually distribute some of these (with your permission), so style counts! Think about what you could imagine receiving as a handout (one-sided or two-sided). Think also about the best designed infographics you have seen and use those as aesthetic inspiration. Please turn in the following:

1. One paragraph describing the kinds of activists for whom you have designed this notice, as well as what assumptions you've made about them.
2. The overview page itself (single-sided or double-sided).
3. Citations to any sources you used to develop the information contained in your overview

Here are some starting resources you might consider when deciding what advice to include or leave out:

• Protecting Your Digital Life in 7 Easy Steps (NY Times)
• Attending Protests in the United States (EFF)
• Things to Consider When Crossing the US Border (EFF)
• The Paranoid Computer User's Guide to Privacy, Security and Encryption (Globe and Mail)
• Crossing the Border? Here's How to Safeguard Your Data From Searches (NY Times)

Problem 4 (25 points)

Write a first draft of the methodology section for your group's research project. For the purpose of the homework assignmet, each team member should do this individually. Afterwards, your team will have a whole set of methodology drafts, which will allow you to combine the strongest aspects of each.

(CMSC 33210 only!) Problem 5 (24 points)

Write 3-7 sentence summaries and short "highlights" for both the Englehardt and Narayanan reading assigned for April 24th and the Wang et al. reading assigned for April 26th.