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.9 Biases That Affect Survey Responses

Pros and Cons of Requiring Survey Responses

4 Things UX Research Tells You that Google Analytics Doesn't

4 Principles to Help Innovate and Improve the Customer Experience

Does better usability increase customer loyalty?

The Five Most Influential Papers in Usability

Nine misconceptions about statistics and usability

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

10 Things to Know about Usability Problems

How common are usability problems?

How to Conduct a Usability test on a Mobile Device

What five users can tell you that 5000 cannot

A Brief History of the Magic Number 5 in Usability Testing

Confidence Interval Calculator for a Completion Rate

Should you use 5 or 7 point scales?

8 Ways to Show Design Changes Improved the User Experience

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Customer Analytics for DummiesA guidebook for measuring the customer experience Buy on Amazon | |

Quantifying the User Experience 2nd Ed.: 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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