Table of Contents
Chapter 1: Introduction and how to use this book
Answers to chapter review questions
Chapter 2: Quantifying user research
Chapter 3: How precise are our estimates? Confidence intervals
Confidence interval for a completion rate
Confidence interval for rating scales and other continuous data
Answers to chapter review questions
Chapter 4: Did we meet or exceed our goal?
One-tailed and two-tailed tests
Comparing a completion rate to a benchmark
Comparing a satisfaction score to a benchmark
Comparing a task time to a benchmark
Answers to chapter review questions
Chapter 5: Is there a statistical difference between designs?
Comparing two means (rating scales and task times)
Comparing completion rates, conversion rates, and A/B testing
Answers to chapter review questions
Chapter 6: What sample sizes do we need? Part 1: summative studies
What can I do to control variability?
Sample size estimation for binomial confidence intervals
Sample size estimation for chi-squared tests (independent proportions)
Sample size estimation for McNemar Exact Tests (matched proportions)
Answers to chapter review questions
Chapter 7: What sample sizes do we need? Part 2: formative studies
Assumptions of the binomial probability model
Additional applications of the model
What is a reasonable problem discovery goal?
Reconciling the “Magic Number Five” with “Eight is Not Enough”
More about the binomial probability formula and its small-sample adjustment
Other statistical models for problem discovery
Answers to chapter review questions
Chapter 8: Standardized usability questionnaires
Questionnaires for assessing perceived usability of websites
Other questionnaires of interest
Answers to chapter review questions
Chapter 9: Six enduring controversies in measurement and statistics
Is it OK to average data from multipoint scales?
Do you need to test at least 30 users?
Should you always conduct a two-tailed test?
Can you reject the null hypothesis when p > 0.05?
Can you combine usability metrics into single scores?
What if you need to run more than one test?
Answers to chapter review questions
Chapter 10: An introduction to correlation, regression, and ANOVA
Coefficient of determination (R2)
Answers to chapter review questions
Appendix: A crash course in fundamental statistical concepts