Blog: Statistics Release notes, how-tos and statistical explainers from the Analyse-it team, newest first.
- 2023
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A New Year. A New Edition
Last year was a productive year for Analyse-it, with the addition of survival analysis functions Kaplan-Meier survival curves and Cox's proportional hazards regression .
- 2022
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Analyse-it 6.10: Survival Analysis and other improvements
We’re happy to announce a couple of major additions to the Analyse-it Ultimate edition: Kaplan-Meier survival curves and Cox’s proportional hazards survival model. There are also improvements for users of other editions.
- 2021
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Analyse-it 5.90: Support for the updated CLSI EP6-Ed2 protocol and inverse predictions
Recently we’ve been busy updating Analyse-it to stay aligned with the latest updates to the CLSI protocols, and added a new inverse prediction feature.
- 2020
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Calculating the detection limit for a SARS-CoV-2 RT-PCR assay using Analyse-it
Recent improvements to the Analyse-it Method Validation edition, in version 5.50 and later, include the addition of probit regression. Probit regression is useful when establishing the detection limit (LoD) for an RT-qPCR assay.
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Calculating PPA/NPA agreement measures using Analyse-it
Following our last blog post, today, we will show how to calculate binary agreement using the Analyse-it Method Validation edition. The CLSI EP12: User Protocol for Evaluation of Qualitative Test Performance protocol is a useful companion resource for laboratories and diagnostic…
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Diagnostic accuracy (sensitivity/specificity) versus agreement (PPA/NPA) statistics
Due to COVID-19, there is currently a lot of interest surrounding the sensitivity and specificity of a diagnostic test. These terms relate to the accuracy of a test in diagnosing an illness or condition.
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Establishing the diagnostic accuracy (sensitivity/specificity) of a test using Analyse-it
It is important in diagnostic accuracy studies that the true clinical state of the patient is known. For example, in developing a SARS-CoV-2 anti-body test, for the positive subgroup, you might enlist subjects who had a positive SARS-CoV-2 PCR test and clinically confirmed…
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Why the diagnostic test 'accuracy' statistic is useless
In our last post, we mentioned that the 'accuracy' statistic, also known as the probability of a correct result, was a useless measure for diagnostic test performance. Today we'll explain why.
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Sensitivity/Specificity and The Importance of Predictive Values for a diagnostic test
There’s currently a lot of press attention surrounding the finger-prick antibody IgG/IgM strip test to detect if a person has had COVID-19. Here in the UK companies are buying them to test their staff, and some in the media are asking why the government hasn’t made millions of…
- 2019
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Training and consultancy for Analyse-it
Our focus at Analyse-it has always been on the development and improvement of our software. While we provide extensive help, tutorials, and technical support for Analyse-it, one area we do not cover is training and consultancy.
- 2017
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Analyse-it 4.90 released: Prediction intervals, EP14-A3 and EP30-A
Prediction intervals on Deming regression are a major new feature in the Analyse-it Method Validation Edition version 4.90, just released.
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Parameter estimation
Often we collect a sample of data not to make statements about that particular sample but to generalize our statements to say something about the population.
- 2015
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The numerical accuracy of Analyse-it against the NIST StRD
A critical feature of any analytical and statistical software is accuracy. You are making decisions based on the statistics obtained and you need to know you can rely on them.
- 2014
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A sombre note: Professor Rick Jones
The recent of passing of Professor Rick Jones (see Rick Jones obituary) caused me to reflect on the past.
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Analyse-it 3.80 released: Principal Component Analysis (PCA)
Today we released version 3.80 of the Analyse-it Standard edition. The new release includes Principal Component Analysis (PCA), an extension to the multivariate analysis already available in Analyse-it.
- 2013
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Quantile and percentile formulas: why Excel, R and SAS give different answers
What is a sample quantile or percentile? Take the 0.25 quantile (also known as the 25th percentile, or 1st quartile) -- it defines the value (let’s call it x) for a random variable, such that the probability that a random observation of the variable is less than x is 0.25 (25%…
- 2008
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Normal quantile plots and Q-Q plots: how to read them
In a previous post, Testing the assumption of Normality, we explained the tests provided in Analyse-it to determine if a sample has normal distribution. In that post, we mentioned that although hypothesis tests are useful you should not solely rely on them.