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ezyStat

Resource centre

Practical material on study design, analysis and reporting. The sample size calculator and FAQs are available now; guides, tutorials and templates are being written.

Resource categories

  • Planned

    Statistical guides

    Plain-language guides to methods and their assumptions.

  • Planned

    Research methodology articles

    Study design, sampling and measurement.

  • Planned

    R and Python tutorials

    Worked code examples with open data.

  • Planned

    Survey design resources

    Question wording, scales and sampling checklists.

  • Planned

    Data analysis examples

    End-to-end examples using public datasets.

  • Available

    Statistical calculators

    Sample size for a proportion is available now. More to follow.

  • Planned

    Downloadable templates

    Analysis plans, questionnaire and report templates.

  • Available

    Frequently asked questions

    Answers about working with ezyStat.

Sample size calculator

How many completed responses do you need to estimate a percentage with a given precision? Adjust the inputs and the result updates as you type.

Confidence level

The precision you need, e.g. 3 for ±3%.

Use 50 if unsure; it gives the largest sample.

Leave blank for a large population.

1 for simple random sampling; often 1.2 to 2 with weighting or clustering.

Used to estimate how many people to invite.

Completed responses needed

1,068

Base sample, n₀ = z²p(1−p)/e²
1067.1
After design effect × 1
1067.1

This applies to estimating one proportion. Comparing subgroups, measuring change or estimating means needs a different calculation. Treat the result as a starting point for discussion, not a final design.

Articles in preparation

These guides are planned. Titles and summaries show the intended scope; they will be published here as they are completed.

  • Survey designPlanned

    How to determine sample size for a survey

    Margin of error, confidence level, subgroups and the effect of weighting, worked through with examples.

  • Statistical guidesPlanned

    Choosing the right statistical test

    A practical route from your research question and data type to an appropriate test or model.

  • Research methodologyPlanned

    Market research versus feasibility studies

    What each one answers, when you need both, and how they fit together.

  • R and Python tutorialsPlanned

    Mixed-effects models in R: a first walkthrough

    Fitting and interpreting a random-intercept model with lme4, using an open dataset.

  • Survey designPlanned

    Survey weighting without the mystery

    Raking, design effects and effective sample size, explained with a small example.

  • R and Python tutorialsPlanned

    Cleaning messy data in Python

    A reproducible pandas workflow for duplicates, missing values and inconsistent categories.

Frequently asked questions

About working with ezyStat.

How do projects usually start?

Send a short description of your project through the enquiry form. We reply to arrange an initial conversation, then send a written proposal setting out the scope, method, timeline and cost.

How are projects priced?

Most work is priced per project after scoping, so you know the cost before work begins. Ongoing support and training can be arranged at an agreed daily or hourly rate.

Should I send my data with my enquiry?

No. Please do not send datasets or personal information through the contact form. If a project goes ahead, we agree a secure way to transfer data and the terms under which it is handled.

Do you work with clients outside the UK?

Yes. We work with international clients remotely. Fieldwork outside the UK is arranged with qualified local partners, subject to project feasibility.

Will you write my thesis or assignment?

No. We provide consultancy, review and training so that you understand and can defend your own analysis, in line with your institution's academic integrity rules.

Which software will you use?

Usually R or Python. Where your organisation works in SPSS, Excel or Power BI, we can deliver in those tools so your team can maintain the work.

Have a research question or data challenge?

Tell us about your project and discover how ezyStat can help you design, analyse and interpret your data.