5. Evaluation Methods

Usability Testing — Quiz

Test your understanding of usability testing with 5 practice questions.

Practice Questions

Question 1

Which threat to internal validity in a within-subject usability study arises when participants’ performance on one condition affects their performance on another?

Question 2

In a paired usability test with n=16 participants, mean task times were 80s for version A and 70s for version B, with the standard deviation of differences at 15s. What is the t-statistic?

Question 3

If the standard deviation of task completion times is 10s, what minimum sample size is required to achieve a 95% confidence interval with a margin of error of $\pm2$ seconds? (Use \$z_{0.975}=1.96\\$)

Question 4

Which data transformation is most appropriate for normalizing a right-skewed distribution of task completion times before parametric analysis?

Question 5

Which composite usability metric technique converts raw task success, time, and error data into standardized scores and aggregates them into a single usability index?