Ben Derrick's Outputs (15)

Preliminary testing: The devil of statistics? (2019)
Journal Article

In quantitative research, the selection of the most appropriate statistical test for the comparison of two-independent samples can be problematic. There is a lack of consensus in the Statistics community regarding the appropriate approach; particular... Read More about Preliminary testing: The devil of statistics?.

Parametric and non-parametric tests for the comparison of two samples which both include paired and unpaired observations (2019)
Journal Article

Samples that include both independent and paired observations cause a dilemma for researchers that covers the full breadth of empirical research. Parametric approaches for the comparison of two samples using all available observations are considered,... Read More about Parametric and non-parametric tests for the comparison of two samples which both include paired and unpaired observations.

An outlier in an independent samples design (2018)
Presentation / Conference Contribution

There is a flaw with some of the most commonly performed statistical tests. A paradox of the one sample t-test is the contrariwise decrease in the p-value as the value of an outlier increases in the direction of the overall effect. Demonstration of t... Read More about An outlier in an independent samples design.

Methods for comparing the responses from a Likert question, with paired observations and independent observations in each of two samples (2018)
Journal Article

Assesses the robustness of the partially overlapping samples t-tests for ordinal samples.

Introduces the Derrick-White Type I error robustness criteria.

To preliminary test or not to preliminary test, that is the question (2018)
Presentation / Conference Contribution

Despite the consequences of violations to the assumptions of statistical tests, there is often neglect in published works to report on the assumptions of the tests performed. Preliminary testing the assumptions prior to preforming the test is done ro... Read More about To preliminary test or not to preliminary test, that is the question.

Tests for equality of variances between two samples which contain both paired observations and independent observations (2018)
Journal Article

Tests for equality of variances between two samples which contain both paired observations and independent observations are explored using simulation. New solutions which make use of all of the available data are put forward. These new approaches are... Read More about Tests for equality of variances between two samples which contain both paired observations and independent observations.

The impact of an extreme observation in a paired samples design (2017)
Journal Article

The effect of systematically altering the value of a single observation within a paired differences design is considered. A paradox is observed for the paired samples t-test, where increasing the value of an observation in the direction of the true m... Read More about The impact of an extreme observation in a paired samples design.

Comparing two samples from an individual Likert question (2017)
Journal Article

For two independent samples there is much debate in the literature whether parametric or non-parametric methods should be used for the comparison of Likert question responses. The comparison of paired responses has received less attention in the lite... Read More about Comparing two samples from an individual Likert question.

Test statistics for the comparison of means for two samples that include both paired and independent observations (2017)
Journal Article

©2017 JMASM, Inc. Standard approaches for analyzing the difference in two means, where partially overlapping samples are present, are less than desirable. Here are introduced two test statistics, making reference to the t-distribution. It is shown th... Read More about Test statistics for the comparison of means for two samples that include both paired and independent observations.

How to compare the means of two samples that include paired observations and independent observations: A companion to Derrick, Russ, Toher and White (2017) (2017)
Journal Article

Standard approaches for comparing the means of two samples, comprising both paired observations and independent observations, involve the discarding of valuable information. An alternative test which uses all of the available data, is the partially o... Read More about How to compare the means of two samples that include paired observations and independent observations: A companion to Derrick, Russ, Toher and White (2017).

Statistics: New t-tests for the comparison of two partially overlapping samples (2017)
Presentation / Conference Contribution

This poster presented for the UWE degree show (June 2017), summarises Type I error rates and Power of standard t-tests and a new generalised form of the t-test, for comparing samples which include both paired and independent observations.

Material... Read More about Statistics: New t-tests for the comparison of two partially overlapping samples.

Partiallyoverlapping: Partially overlapping samples t-tests (2017)
Other

R package for calculating the partially overlapping samples t-test

Why Welch’s test is Type I error robust (2016)
Journal Article

The comparison of two means is one of the most commonly applied statistical procedures in psychology. The independent samples t-test corrected for unequal variances is commonly known as Welch’s test, and is widely considered to be a robust alternativ... Read More about Why Welch’s test is Type I error robust.

Test statistics for comparing two proportions with partially overlapping samples (2015)
Journal Article

Standard tests for comparing two sample proportions of a dichotomous dependent variable where there is a combination of paired and unpaired samples are considered. Four new tests are introduced and compared against standard tests and an alternative p... Read More about Test statistics for comparing two proportions with partially overlapping samples.

An inverse normal transformation solution for the comparison of two samples that contain both paired observations and independent observations
Journal Article

Inverse normal transformations applied to the partially overlapping samples t-tests by Derrick et.al. (2017) are considered for their Type I error robustness and power. The inverse normal transformation solutions proposed in this paper are shown to m... Read More about An inverse normal transformation solution for the comparison of two samples that contain both paired observations and independent observations.