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Quantitative Usability, Statistics & Six Sigma by Jeff Sauro

Tags

Tag: Sample Size

Related Tags

Tag Name #
Confidence Intervals 723
Calculator 406
Task Completion 328
Completion Rate 287
Graph 246
Discrete Data 245
binomial 240
Binomial Probability 238
Task Time 227
UI Problems 224
Tasks 163
Task Success 144
Median 138
Adjusted Wald 134
sample 2 126
19683 124
test statistic 119
82 118
Log Transformation 118
z score 118
Continuous Data 117
Margin of Error 110
Geometric Mean 108
error 104
t-test 99
Non-Normal Data 98
St Deviation 98
Hypothesis Test 94
likelihood ratio test 94
Confidence Level 92
Geometric Standard Deviation 89
p-value 88
log plot 86
skewness 86
Users Needed 83
Normal Curve 82
Power 79
pearson 79
chi square 78
kappa 77
probit regression 76
critical z 75
Wilson 74
Unit Conversion within Customary Units 72
Proportion 58
bmi 53
133 46
20 44
1133 36
1292 28
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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 )