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Preliminary testing: The devil of statistics? (2019)
Journal Article
Pearce, J., & Derrick, B. (2019). Preliminary testing: The devil of statistics?. https://doi.org/10.31273/reinvention.v12i2.339

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?.

An outlier in an independent samples design (2018)
Presentation / Conference
Derrick, B. (2018, September). An outlier in an independent samples design. Paper presented at Royal Statistical Society Conference

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.

To preliminary test or not to preliminary test, that is the question (2018)
Presentation / Conference
Derrick, B. (2018, July). To preliminary test or not to preliminary test, that is the question

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
Derrick, B., Ruck, A., Toher, D., & White, P. (2018). Tests for equality of variances between two samples which contain both paired observations and independent observations

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.

Parametric and non-parametric tests for the comparison of two samples which both include paired and unpaired observations (2018)
Journal Article
Derrick, B., White, P., & Toher, D. (2018). Parametric and non-parametric tests for the comparison of two samples which both include paired and unpaired observations. Journal of modern applied statistical methods : JMASM,

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.

The impact of an extreme observation in a paired samples design (2017)
Journal Article
Derrick, B., Broad, A., Toher, D., & White, P. (2017). The impact of an extreme observation in a paired samples design

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.

Statistics: New t-tests for the comparison of two partially overlapping samples (2017)
Presentation / Conference
Derrick, B. (2017, June). Statistics: New t-tests for the comparison of two partially overlapping samples. Poster presented at Faculty of Environment and Technology Degree Show

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.

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
Derrick, B., Toher, D., & White, P. (2017). How to compare the means of two samples that include paired observations and independent observations: A companion to Derrick, Russ, Toher and White (2017). Quantitative Methods for Psychology, 13(2), 120-126. https://doi.org/10.20982/tqmp.13.2.p120

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).

Test statistics for the comparison of means for two samples that include both paired and independent observations (2017)
Journal Article
Derrick, B., Russ, B., Toher, D., & White, P. (2017). Test statistics for the comparison of means for two samples that include both paired and independent observations. Journal of modern applied statistical methods : JMASM, 16(1), 137-157. https://doi.org/10.22237/jmasm/1493597280

©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.

Why Welch’s test is Type I error robust (2016)
Journal Article
Derrick, B., Toher, D., & White, P. (2016). Why Welch’s test is Type I error robust. Quantitative Methods for Psychology, 12(1), 30-38

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
Derrick, B., Dobson-Mckittrick, A., Toher, D., & White, P. (2015). Test statistics for comparing two proportions with partially overlapping samples

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
Derrick, B., White, P., & Toher, D. An inverse normal transformation solution for the comparison of two samples that contain both paired observations and independent observations

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.