Tags
Tag: Confidence Intervals
Pages
The following pages have the tag
Confidence Intervals associated with them. The number of users that have also tagged the page ' Confidence Intervals ' is in parenthesis.
Confidence Interval Calculator for a Completion Rate ( 236 )
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.
Calculating Sample Size for Task Times (Continuous Method) ( 219 )
Restoring Confidence in Usability Results ( 154 )
Adding confidence intervals to completion rates in usability tests will temper both excessive skepticism and overstated usability findings. Confidence intervals make testing more efficient by quickly revealing unusable tasks with very small samples.
Graph and Calculator for Confidence Intervals for Task Times ( 143 )
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.
Sample Size Calculator for a Completion Rate ( 125 )
Use this interactive calculator to understand how the sample size changes will affect the confidence interval around a completion rate.
Interactive Graph of the Standard Normal Curve ( 38 )
Use this interactive normal curve to understand how the z-score and the area of the curve are related. Offers both one and two-sided options.
Questions
The following questions have the tag
Confidence Intervals associated with them. The number of users that have also tagged the question ' Confidence Intervals ' is in parenthesis.
Hi Jeff thanks for all your help so far, your answers have been great and very timely. It is great t. . . ( 1 )
Linemarking for parking bays shall be determined by the retroreflectivity performance of glass beads. . . ( 1 )
Find the margin or error for the 95% confidence interval used to estimate the population proportion.. . . ( 4 )
Philadelphia is conducting a study on the characteristics of tourists who drive to Eagles football g. . . ( 4 )
Use the given degree of confidence and sample data to construct a confidence interval for the popula. . . ( 4 )
The width of a confidence estimate for a proportion will be:
a. Narrower for a 99% confidence inter. . . ( 4 )
Your company asks you to compare a new advertising campaign and the old one. Sample data on the acco. . . ( 4 )
A machine produces 3 inch nails. A sample of 100 nails is selected, and it is found that 25 are sho. . . ( 4 )
A researcher expects the population proportion of the Cubs Fans in Chicago to be 80%. Error of less . . . ( 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. . . . ( 4 )
Calculate a 98% confidence interval for the following data 15.7,15.7,15.5,15.2,15.2,15.1,15.3.. . . ( 4 )
Calculate the 95% confidence interval on the following GPA's from 30 randomly selected students.
0.. . . ( 4 )
Administrative staff based at a business school in the UK are advised to take a 15 minute break from. . . ( 4 )
A random sample of n=64 children of working mothers showed that they were absent from school an aver. . . ( 4 )
Find a confidence interval for the mean assuming that each sample is from a normal population. Mean . . . ( 4 )
Assume that the heights of 5 year old boys are normally distribued with a mean of 100cm and a standa. . . ( 4 )
A central university has a student population of 60,000. The university is interested in determining. . . ( 4 )
A telescope manufacturer wants its telescopes to have standard deviations in resolution to be signif. . . ( 5 )
In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be engaged. . . ( 3 )
A sample of the math test scores of 35 fourth-graders has a mean of 82 with a standard deviation of . . . ( 3 )
Based on information obtained from a sample of 54, a 98% confidence interval for the average profit . . . ( 3 )
How can I compute a one-sided 97.5% confidence interval using SPSS for this ?
IN a cohort of 121 e. . . ( 3 )
An engineer in an automotive factory wishes to know what the tire pressure is on all cars leaving th. . . ( 4 )
Briefly describe the concept of a confidence interval and provide an example.. . . ( 4 )
A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on very . . . ( 22 )
A sample of 20 pages was taken without replacement from the 1,591-page phone directory Ameritech Pag. . . ( 4 )
Popcorn kernels take between 100 and 200 seconds to pop. What sample size (number of kernels) would . . . ( 4 )
Biting an unpopped kernel of popcorn hurts! As an experiment, a self-confessed connoisseur of cheap . . . ( 3 )
As an experiment, a self-confessed connoisseur of cheap popcorn carefully counted 773 kernels and pu. . . ( 3 )
An engineer in an automotive factory wishes to know what the tire pressure is on all cars leaving th. . . ( 4 )
out of a random sample 167 students pass an exam out of the 300. how do you calculate an exact 99% c. . . ( 4 )
The Web-based company Oh Baby! Gifts has a goal of processing 95 percent of its orders on the same d. . . ( 5 )
Determine the critical value Za/2 that corresponds to 94% level of confidence
Compute the 90% con. . . ( 4 )
Jeff:
Can you possibly share the actual formula you are using in this application to produce the . . . ( 4 )
Annual starting salaries for college graduates with degrees in business administration are generally. . . ( 7 )
I am charged with sampling expense report submissions for accuracy. We get 8000 T&E claims, and wan. . . ( 5 )
How would I figure out a 90% and 95% confidence interval for the below informaion? What would be th. . . ( 5 )
In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be engaged. . . ( 5 )
how to calculate one sided 95% confidence limits for a proportion.could you provide a formula . . . ( 5 )
When calculating confidence interval estimates...how is the x and standard deviation calculated?. . . ( 6 )
I am trying to do A/B testing onweb page displays. One is the test the other is the control.
Could . . . ( 7 )
in a sample of 1000 tv vieweres 330 watched a particlar programme. find 99 pecent confidence limits . . . ( 5 )
If 350 respondents out of a random sample of 1,000 Americans reported that they did not trust their . . . ( 5 )
A random sample of 25 households finds that an average of 2.3 people reside in each house (the stand. . . ( 5 )
what is the value of z score required for a 70% confidence interval?. . . ( 6 )
Why don't statisticians calculate 100% confidence intervals?. . . ( 5 )
What is the Z score of a 98% confidence interval?. . . ( 4 )
