Measuring Usability
Quantitative Usability, Statistics & Six Sigma by Jeff Sauro

Survey Sample Size Package

Download a 27 page how-to guide and calculator to compute sample sizes for rating scales and binary responses. This package allows you to easily answer the common question: What sample size do I need for my survey?
Screen Shots of
Click for more details on this screen shot Click for more details on this screen shot Click for more details on this screen shot Click for more details on this screen shot Click for more details on this screen shot More...

    $59.00     Now :  

If you will be making copies or distributing the product, please purchase the site license

Benefits & Features

  • What Sample Size do I need for this survey? How many times have you heard or said that? This package solves your problems by providing calculators, explanations, formulas and plenty of tips for navigating sample size questions.
  • The math is done for you! If you think sample size calculations are magic and not math, the guide and real-time calculations will show you how it's possible to generate reliable sample size estimates.
  • Built in Industry Assumptions Not sure what standard deviation to use? The calculator has built in benchmarks from Market Research that allows you to be intelligent predictions about sample size.
  • Sample Size for Proportion of Promoters If you use the popular Net Promoter question (Are you likely to recommend a product to a friend?) this guide shows you how to compute the right sample size for finding the percent promoters and a new confidence interval calculator around a Net Promoter Score
  • Confidence Interval BONUS As an added bonus, I've included three confidence interval calculators. These calculators allow you to understand the margin of error before and after you sample for a Net Promoter Score, Binary Response and Rating Scale response.

Demo




Who Should Buy

Market Researchers, User Researchers, Usability Professionals, or anyone who has to plan or analyze surveys.

Table of Contents

Steps to Find a Sample Size
1. How are you asking the questions?
2. How precise do you need to be (d)
3. Estimate the Standard Deviation:
  a For Binary Data
  b.For Rating Scales
4. Determine your confidence level:
5. Find the Sample Size using the correct formula:
Additional Considerations
   What to do with non-numeric responses
   Using Top Box or Top-Two Box:
   Combining Multiple Rating Scales:
Open Ended Numeric Responses:
Practice Questions
Practice Answers
Calculator Example 1: Sample Size for a Binary Response
Calculator Example 2: Sample Size for a Rating Scale Response
Calculator Example 3: Confidence Interval around a Rating Scale Average
Calculator Example 4: Confidence Interval around a Binary Response
References
About the Author

Select Sample Screen Shots

Report and Calculator Package

Report and Calculator Package

Sample size questions are common but complex. This report and calculator makes the concepts easier to understand and implement.

27 Page Guide on Computing Sample Sizes

27 Page Guide on Computing Sample Sizes

This guide has a five-step process for finding the right sample size for your survey. It includes four detailed example questions as well as five practice exercises and answers, and show you how to find sample sizes for the Net Promoter score.

Sample Size Calculator for Rating Scales

Sample Size Calculator for Rating Scales

Just enter your desired level of precision (e.g. half-a-point) and the number of response options and the calculator provides you with the sample size. It uses industry benchmarks if you don't know the standard deviation (explained in detail in the 23 page report).

Sample Size Calculator for Binary Responses

Sample Size Calculator for Binary Responses

Do users agree or disagree with statements, are they promoters or detractors? Binary responses (only two option responses) are one of the most common response types in surveys. Just enter the desired margin of error (and optional percentage) and the calculator gives you the needed sample size.

Simple Instructions for using the calculator

Simple Instructions for using the calculator

The report walks you through a five step process (through four detailed examples) and allows you to intelligently frame sample size questions by understanding the important concepts of precision, confidence and variability.

Plenty of Practice questions available to match your specific need

Plenty of Practice questions available to match your specific need

With five practice questions and detailed answers you should have no problem understanding how the formulas generate the results. No need to dig through old college statistics textbooks for arcane explanations.

Deatiled explanations of the formulas

Deatiled explanations of the formulas

No one likes to memorize formulas. The guide shows you the basic components of the sample size formulas, how they are derived from confidence interval formulas and some short-cuts for quickly and accurately computing sample sizes.

Confidence Interval for Binary Responses

Confidence Interval for Binary Responses

As a bonus, I've included a confidence interval calculator for binary responses. This way, you can both predict your sample size and report your margin of error after you collect your data.

Confidence Interval for Rating Scales

Confidence Interval for Rating Scales

As a bonus I've also included two confidence interval calculators for rating scale data. This allows you to generate standard deviation estimates from past data and and report your margin of error after you collect your data (using both summary data and raw data).

Estimating a Needed Sample Size from a Sample Response Rate

Estimating a Needed Sample Size from a Sample Response Rate

Use this calculator to estimate the total number of invites you need to send out in order to maintain a desired margin of error (e.g. 5%).

Confidence Interval for a Net Promoter Score

Confidence Interval for a Net Promoter Score

A Net Promoter Score is based on two dependent proportions (promoters and detractors). This confidence interval calculator uses the most accurate method for any sized sample and it works when the NPS is negative.

Package Features

  • Sample Size for Rating Scales
  • Sample Size for Binary Data
  • A 27 Page step-by-step guide for understanding and using sample size formulas
  • Confidence Interval for Binary Responses
  • Confidence Interval for Rating Scales (Summary Data)
  • Confidence Interval for Rating Scales (Raw Data)
  • NEW: Sample Size Needed based on a Response Rate
  • NEW: Confidence Interval for a Net Promoter Score



    $59.00     Now :  

If you will be making copies or distributing the product, please purchase the site license All major credit cards, debit cards and PayPal Accepted.
.
.
.