Jeff Sauro • December 4, 2007

Enter the area under the normal curve (a proportion between 0 & 1) and get the Z-critical value, one-sided or two-sided. To convert a Z-Score into a percentage use the Z-Score to Percentile Calculator. See also the interactive Graph of the Standard Normal Curve.Download this calculator in an excel file or take a Crash course in Z-scores

10 Things to Know about a Key Driver Analysis

12 Tips For Writing Better Survey Questions

8 Ways to Show Design Changes Improved the User Experience

Confidence Interval Calculator for a Completion Rate

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

10 Things to Know about Usability Problems

Nine misconceptions about statistics and usability

Does better usability increase customer loyalty?

How common are usability problems?

97 Things to Know about Usability

The Five Most Influential Papers in Usability

A Brief History of the Magic Number 5 in Usability Testing

How to Conduct a Usability test on a Mobile Device

5 Examples of Quantifying Qualitative Data

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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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