Jeff Sauro • February 6, 2006

This calculator takes raw task times, transforms them using the Natural Logarithm and computes a confidence interval. The values are displayed in the dot-plots graph below. You can also download an excel version of this calculator.3 Days of Hands-On Training on User Experience Methods, Metrics and Analysis.Learn More

Should the Net Promoter Score Go? 5 Common Criticisms Examined

5 Variables to Manage in a Comparative Usability Study

Confidence Interval Calculator for a Completion Rate

5 Examples of Quantifying Qualitative Data

Nine misconceptions about statistics and usability

How to Conduct a Usability test on a Mobile Device

What five users can tell you that 5000 cannot

Should you use 5 or 7 point scales?

How common are usability problems?

97 Things to Know about Usability

8 Ways to Show Design Changes Improved the User Experience

A Brief History of the Magic Number 5 in Usability Testing

Does better usability increase customer loyalty?

Why you only need to test with five users (explained)

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Quantifying the User Experience: Practical Statistics for User ResearchThe most comprehensive statistical resource for UX Professionals Buy on Amazon | |

Excel & R Companion to Quantifying the User ExperienceDetailed Steps to Solve over 100 Examples and Exercises in the Excel Calculator and R Buy on Amazon | Download | |

A Practical Guide to the System Usability ScaleBackground, Benchmarks & Best Practices for the most popular usability questionnaire Buy on Amazon | Download | |

A Practical Guide to Measuring Usability72 Answers to the Most Common Questions about Quantifying the Usability of Websites and Software Buy on Amazon | Download |

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