Julie Pallant's
Statistics Survival Hub
Practical tools and guidance for choosing and
using statistical tests
This site brings together tools and step-by-step guides to help students and researchers feel more confident when
analysing data
Why I created this hub
Over many years of teaching and writing about statistics, I have seen how confusing and stressful data analysis can be for many students and researchers. I wrote the SPSS Survival Manual to provide clear, step-by-step guidance for those who needed practical help carrying out statistical analyses in SPSS.
This site is a natural extension of that same goal. It has been designed to provide additional resources to help you choose the most appropriate statistical test and calculate your sample size.
Many students and researchers feel lost when it comes to statistics
How this hub helps
Understand your study
Clarify what your research question is really asking. Identify the variables involved.
Calculate sample size
Use the Sample Size Calculator to determine the number of cases you need in your study.
Prepare your data
Check what needs to be done before analysis begins.
Choose a statistical test
Use the Stats Selection Tool to identify a likely statistical approach.
Run the analysis
Use the SPSS Survival Manual or your preferred resource for a step-by-step guide to running the statistical analyses.
Interpret and write up
Understand what the results mean and how to present them correctly.
Tools
The Statistics Hub includes three practical tools designed to support you at different stages of the research process.
The Stats Selection Tool helps you work out which statistical analysis is most appropriate for your research question and your data.
The Sample Size Calculator can help you estimate the number of participants you may need when planning your study.
The Effect Size Calculator helps you calculate, convert, or extract effect size information for sample size planning, result interpretation, and research reporting.
Together, these tools are intended to make study planning and data analysis more manageable by providing clear guidance and helping you feel more confident about the decisions you need to make.
Stats Selection Tool
One of the hardest parts of statistics is working out which analysis is appropriate for your data and research question. The statistical test selector has been designed to help with that step. It guides you through a series of questions and helps narrow down the statistical approach that is most likely to suit your needs.
Where relevant, the selector will also point you to the corresponding chapter in the SPSS Survival Manual for detailed instructions to run the analyses. If you do not have the SPSS Survival Manual, you can still use the result as a guide and to use the statistical resource you already use for instructions on how to conduct the test.
If you need some help understanding statistical jargon and the steps involved in exploring and preparing your data, click here for some helpful tips and hints.
If you have a good understanding of your research question and the characteristics of your data click here to go directly to the Stats Selection Tool
Sample Size Calculator
Choosing an appropriate sample size is an important part of study design. If your sample is too small, you may not detect important effects. If it is too large, you may spend more time and resources than necessary. Estimating sample size early helps you plan a stronger and more efficient study.
This Sample Size Calculator is designed for basic and commonly used statistical procedures. It is intended as a practical guide to support study planning. For more complex models, refer to G*Power which can be accessed for free.
Effect Size Calculator
The Effect Size Calculator is designed to help you work out how large and meaningful a result really is. It can be used to calculate an effect size from reported results, convert between common effect size measures, or help you extract an effect size from information provided in published research.
This is especially useful when planning a study, because an estimate of effect size is often needed for a sample size calculation. If previous studies do not report the effect size clearly, this tool can help you obtain the information needed to estimate how many participants or cases your study may require. It is also useful when interpreting your results or preparing a report, thesis, or journal article. Many journals now require you to report an effect statistic in addition to a p value.
These tools are intended as a guide only. They do not replace careful consideration of your study design, your discipline-specific literature, or professional statistical advice. Where appropriate, please consult a qualified statistician, supervisor, or research adviser before making final decisions.
How to use these tools together
These three tools are designed to help at different stages of planning and reporting a study. The best place to start is with the Stats Selection Tool. This helps you work out which statistical test is most likely to suit your research question, study design, and type of data. For example, it can help you decide whether you are likely to need a t-test, ANOVA, correlation, regression, chi-square, or another common analysis.
Once you have identified the statistical test you expect to use, the next step is the Sample Size Calculator. This tool helps you estimate how many participants or cases you may need for that planned analysis. A sample size calculation is not based on guesswork. It usually requires four main pieces of information: the statistical test you plan to use, the significance level you want to adopt, the level of statistical power you want to achieve, and an estimate of the effect size you expect to find.
Effect size is a very important part of sample size planning because it reflects how large or strong you expect the result to be. In general, small effects require larger samples to detect, while larger effects can be detected with smaller samples. Ideally, your estimate of effect size should be based on previous research in your area, especially studies that used similar measures, groups, or designs. However, this information is not always available. When that happens, researchers often use general guidelines for small, medium, or large effects as a starting point, while recognising that this is only an estimate.
The Effect Size Calculator is provided for situations where you need help working out, converting, or interpreting an effect size. This may be useful when you are reviewing previous studies and need an effect size estimate for your sample size calculation, or later when you are writing up your results and want to report the size of an effect clearly. It is not always necessary to use this tool. In some cases, previous studies already report suitable effect sizes, or your statistical software may provide an effect size automatically for certain analyses.
In simple terms, the usual order is this: first decide which analysis you are likely to use, then estimate how large your sample may need to be, and use the Effect Size Calculator only when you need extra help with the effect size part of the process.
Together, these tools are designed to make the planning and reporting of quantitative research clearer and less intimidating.
Please share any feedback you have on the tool using the button below. Let me know what you liked, what you struggled with or any suggestions for improvement.
I will be regularly adding new tools, resources, tips and hints to this Statistics Survival Hub. If you would like to receive news of updates, please subscribe to my newsletter.