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.The New Face of Usability Testing

7 Techniques for Prioritizing Customer Requirements

How to Compute a Confidence Interval in 5 Easy Steps

The Experiment Requires That You Continue: On The Ethical Treatment of Users

The Five Most Influential Papers in Usability

A Brief History of the Magic Number 5 in Usability Testing

5 Examples of Quantifying Qualitative Data

Should you use 5 or 7 point scales?

97 Things to Know about Usability

How common are usability problems?

Confidence Interval Calculator for a Completion Rate

How to Conduct a Usability test on a Mobile Device

What five users can tell you that 5000 cannot

Nine misconceptions about statistics and usability

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

Does better usability increase customer loyalty?

8 Ways to Show Design Changes Improved the User Experience

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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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