Anmerkungen:
Includes bibliographical references and index
Beschreibung:
Cover ; Title Page; Copyright Page; Dedication; Contents; Biographies; Foreword; Preface to the Second Edition; Acknowledgments; Chapter 1 -- Introduction and how to use this book; Introduction; The organization of this book; How to use this book; What test should I use?; What sample size do I need?; You don't have to do the computations by hand; Key points; Chapter review questions; Answers to chapter review questions; References; Chapter 2 -- Quantifying user research; What is user research?; Data from user research; Usability testing; Sample sizes; Representativeness and randomness
Computing the geometric meanLog transforming confidence intervals for task-time data; Confidence interval for large sample task times; Confidence interval around a median; Key points; Chapter review questions; Answers to chapter review questions; References; Chapter 4 -- Did we meet or exceed our goal?; Introduction; One-tailed and two-tailed tests; Comparing a completion rate to a benchmark; Small sample test; Mid-probability; Large sample test; Comparing a satisfaction score to a benchmark; Do at least 75% agree? converting continuous ratings to discrete
Disadvantages to converting continuous ratings to discreteNet Promoter Score; Comparing a task time to a benchmark; Key points; Chapter review questions; Answers to chapter review questions; References; Chapter 5 -- Is there a statistical difference between designs?; Introduction; Comparing two means (rating scales and task times); Within-subjects comparison (paired t-test); Confidence interval around the difference; Practical significance; Comparing task times; Normality assumption of the paired t-test; Between-subjects comparison (two-sample t-test); Confidence interval around the difference
Three types of studies for user researchData collection; Completion rates; Usability problems (UI problems); Task Time; Errors; Satisfaction ratings; Combined scores; A/B testing; Clicks, page views, and conversion rates; Survey data; Rating scales; Net Promoter Scores; Comments and open-ended data; Requirements gathering; Key points; References; Chapter 3 -- How precise are our estimates? Confidence intervals; Introduction; Confidence interval = twice the margin of error; Confidence intervals provide precision and location; Three components of a confidence interval; Confidence level
VariabilitySample size; Confidence interval for a completion rate; Confidence interval history; Wald interval: terribly inaccurate for small samples; Exact confidence interval; Adjusted-Wald: add two successes and two failures; Best point estimates for a completion rate; Guidelines on reporting the best completion rate estimate; How accurate are point estimates from small samples?; Confidence interval for a problem occurrence; Confidence interval for rating scales and other continuous data; Confidence interval for task-time data; Mean or median task time?; Variability; Bias; Geometric mean