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Quantitative Usability, Statistics & Six Sigma by Jeff Sauro

Tags

Tag: Sample Size

Pages

The following pages have the tag Sample Size associated with them. The number of users that have also tagged the page ' Sample Size ' is in parenthesis.

Calculating Sample Size for Task Completion (Discrete-Binary Method) ( 170 )

Sample Size Calculator for a Completion Rate ( 166 )
Use this interactive calculator to understand how the sample size changes will affect the confidence interval around a completion rate.

Sample Size Calculator for Discovering Problems in a User Interface ( 137 )
Use this calculator to determine the number of users you'd need to test given the probability of detecting a problem. If the probability of detecting the problem is unknown, this calculator also allows you to estimate the problem occurrence (p) from sample data.

Calculating Sample Size for Task Times (Continuous Method) ( 119 )

Confidence Interval Calculator for a Completion Rate ( 116 )
If you've wanted to provide a confidence interval around a small sample completion rate but just didn't have time to do the math, this calculator does the work for you.

Margins of Error in Usability Tests ( 104 )
The 20/20 Rule of PrecisionHow many users will complete the task and how long will it take them? If you need to benchmark an interface, then a summative usability test is one way to answer these questions. Summative tests are the gold-standard for usability measurement. But just how precise are the metrics?

Graph and Calculator for Confidence Intervals for Task Times ( 90 )
Visualizing your task time data is an essential step in understanding its distribution and computing accurate confidence intervals. This calculator creates a dot-plot of your task times, transforms the raw data to adjust for non-normality and computes the intervals.

Deriving a Problem Discovery Sample Size ( 73 )
Side-bar to The Risks of Discounted Qualitative Studies:Shows the history and computation of deriving a sample size for discovering problems in an interface.

Questions

The following questions have the tag Sample Size associated with them. The number of users that have also tagged the question ' Sample Size ' is in parenthesis.

An automobile manufacturer wants to estimate the mean gasoline mileage that its customers will obtai. . . ( 1 )

Philadelphia is conducting a study on the characteristics of tourists who drive to Eagles football g. . . ( 4 )

When estimating the mean of a population, how large must the sample be in order that the 95% error m. . . ( 4 )

Survey to determine what proportion of new car buyers continue to have their car serviced at the dea. . . ( 4 )

A researcher expects the population proportion of the Cubs Fans in Chicago to be 80%. Error of less . . . ( 4 )

In a national wide survey a researcher expects 30 percent of the population will agree with an value. . . ( 4 )

In a survey of 500, 60% responded positively to an value question. Calculate a confidence level at. . . ( 4 )

Suppose you are planning a sample of employees to determine the monthly average # of vacation days. . . . ( 5 )

The EPA range for a car is 20-28mpg, how large of a sample would be required to estimate your mean m. . . ( 4 )

A central university has a student population of 60,000. The university is interested in determining. . . ( 4 )

A central university has a student population of 60,000. The university is interested in determining. . . ( 4 )

A researcher is interested in estimating the average salary of fire fighters in a large city. He wan. . . ( 3 )

Can you give me a formula to calculate sample size?. . . ( 4 )

A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on very . . . ( 4 )

A sample of 20 pages was taken without replacement from the 1,591-page phone directory Ameritech Pag. . . ( 3 )

Popcorn kernels take between 100 and 200 seconds to pop. What sample size (number of kernels) would . . . ( 4 )

My question is really about sample size. Say you work at a facility and want to perform an assessme. . . ( 4 )

I am charged with sampling expense report submissions for accuracy. We get 8000 T&E claims, and wan. . . ( 5 )

State the main points of the Central Limit Theorem for a mean. B. Why is population shape of concern. . . ( 4 )

How to determine the sample size for comparing mulltiple parameters like Height , weight, Blood pre. . . ( 4 )

Annual starting salaries for college graduates with degrees in business administration are generally. . . ( 3 )

How do you determine the sample size for data for which the mean and standard deviation are not know. . . ( 13 )