Calculators

A/B Test Calculator

Compare two independent proportions for A/B testing or comparing completion rates or conversion rates for small and large sample sizes.

Confidence Interval Calculator

Compute confidence intervals around continuous data using either raw or summary data.

Compare 2 Small Sample Completion Rates (Fisher Exact Test)

Use this calculator to determine if there is a significant difference between 2 small sample completion rates.

One Sample Proportion Calculator

Use this calculator to generate both a one-sample confidence interval and to test against a critera or benchmark.

Sample Size Calculator for a Completion Rate

Use this calculator to understand how sample size changes will affect the confidence interval around a completion rate.

Interactive Graph of the Standard Normal Curve

Hover over the normal curve to display the area and z-score.To enter specific values use the Z-Score to Percentile Calculator or the Percentile to Z-Score Calculator.

Percentile to Z-Score Calculator

Enter the area under the normal curve (a proportion between 0 & 1) and get the Z-critical value, one-sided or two-sided.

Z-Score to Percentile Calculator

Enter a z-critical value and get the area under the normal curve (a percentage). Selecting two-sided provides the area above Z and below -Z.

Sample Size Calculator for Discovering Problems in a User Interface

This calculator produces an estimate of the number of users needed to discover the specified percent of total problems. It uses the Good-Turing and Normalization procedure.

Graph and Calculator for Confidence Intervals for Task Times

This calculator takes raw task times, them using the Natural Logarithm and computes a confidence interval. The values are displayed in the dot-plots graphs.

One Sample Proportion Calculator

Use this calculator to generate both a one-sample confidence interval and to test against a critera or benchmark.

Sample Size Calculator for a Completion Rate

Use this calculator to understand how sample size changes will affect the confidence interval around a completion rate.

Sample Size Calculator for Discovering Problems in a User Interface

This calculator produces an estimate of the number of users needed to discover the specified percent of total problems. It uses the Good-Turing and Normalization procedure.

A/B Test Calculator

Compare two independent proportions for A/B testing or comparing completion rates or conversion rates for small and large sample sizes.

Compare 2 Small Sample Completion Rates (Fisher Exact Test)

Use this calculator to determine if there is a significant difference between 2 small sample completion rates.

Percentile to Z-Score Calculator

Enter the area under the normal curve (a proportion between 0 & 1) and get the Z-critical value, one-sided or two-sided.

Z-Score to Percentile Calculator

Enter a z-critical value and get the area under the normal curve (a percentage). Selecting two-sided provides the area above Z and below -Z.

Confidence Interval Calculator

Compute confidence intervals around continuous data using either raw or summary data.

Interactive Graph of the Standard Normal Curve

Hover over the normal curve to display the area and z-score.To enter specific values use the Z-Score to Percentile Calculator or the Percentile to Z-Score Calculator.

Graph and Calculator for Confidence Intervals for Task Times

This calculator takes raw task times, them using the Natural Logarithm and computes a confidence interval. The values are displayed in the dot-plots graphs.