Comparing the asymptotic power of exact tests in 2×2 tables

Andrés, Antonio Martín; Mato, Agustín Silva; Tapia, José Miguel Rodríguez; Quevedo, M. J. Sánchez

doi:10.1016/j.csda.2003.11.012

Cited by 21 publications

(5 citation statements)

References 14 publications

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“…Since one of the four comparisons had at least one cell with an expected N of less than five, chi square tests were not appropriate. Fisher's exact test is commonly used in such situations, although there have been suggestions that it is overly conservative with small samples (Martín Andrés et al, 2004); thus, we chose to employ Barnard's exact test to compare distribution differences, although we also report results of Fisher's exact test. In addition to tests of significance, odds ratios were calculated for each comparison, when possible.…”

Section: Methodsmentioning

confidence: 99%

Revisiting the blurry boundaries of schizophrenia: Spectrum disorders in psychometrically identified schizotypes

Bolinskey

James

Cooper-Bolinskey

et al. 2015

Psychiatry Research

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Section: Methodsmentioning

confidence: 99%

Revisiting the blurry boundaries of schizophrenia: Spectrum disorders in psychometrically identified schizotypes

Bolinskey

James

Cooper-Bolinskey

et al. 2015

Psychiatry Research

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“…This may lead to markedly lower sample sizes, even in moderately large samples. For example, to test for a difference in binomial proportions when 1 = 0.03, 2 = 0.2, and = 0.05, the sample size needed for 80 per cent power is 60 per group with Fisher's exact test and 52 per group with Fisher-Boschloo's unconditional tests, even though Martín Andrés et al [40] report the conditional test to be acceptable in this case based on an average power consideration. In general, there should be no reason to condition on quantities not fixed by the design.…”

Section: Conditional or Unconditional Testsmentioning

confidence: 99%

Recommended tests for association in 2×2 tables

Lydersen

Fagerland

Laake

2009

Statistics in Medicine

270

210

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The asymptotic Pearson's chi-squared test and Fisher's exact test have long been the most used for testing association in 2x2 tables. Unconditional tests preserve the significance level and generally are more powerful than Fisher's exact test for moderate to small samples, but previously were disadvantaged by being computationally demanding. This disadvantage is now moot, as software to facilitate unconditional tests has been available for years. Moreover, Fisher's exact test with mid-p adjustment gives about the same results as an unconditional test. Consequently, several better tests are available, and the choice of a test should depend only on its merits for the application involved. Unconditional tests and the mid-p approach ought to be used more than they now are. The traditional Fisher's exact test should practically never be used.

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“…Multiplex amplification reactions were carried out as previously stated but using Folmer et al (1994) (LCO1490: 5'-GGT-CAACAAATCATAAAGATATTGG-3'; HCO2198: 5'-TAAACTTCAGGGTGACCAAAAAATCA-3') and Darling et al (2008) (COIF-PR115: 5'-TCWAC-NAAYCAYAARGAYATTGG-3'; COIR-PR114: 5'-ACYTCNGGRTGNCCRAARARYCA-3') mitochondrial cytochrome oxidase I (COI) primers at 45°C annealing temperature for 30 s. A one-side Fisher's exact probability test was carried out on the PCR success/failure table for the green/orange DNA as implemented in the function fisher.test of the stats package in R v2.9.1 (R Development Core Team, 2009). Fisher's exact probability test is recommended in order to test for differences in success rates from two-by-two contingency tables with moderate sample sizes (Martín Andrés et al, 2004).…”

Section: Methodsmentioning

confidence: 99%

DNA extraction from formalin-fixed tissue: new light from the deep sea

Palero¹,

Hall²,

Clark³

et al. 2010

Sci. Mar.

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SUMMARY: DNA samples were extracted from ethanol and formalin-fixed decapod crustacean tissue using a new method based on Tetramethylsilane (TMS)-Chelex. It is shown that neither an indigestible matrix of cross-linked protein nor soluble PCR inhibitors impede PCR success when dealing with formalin-fixed material. Instead, amplification success from formalin-fixed tissue appears to depend on the presence of unmodified DNA in the extracted sample. A staining method that facilitates the targeting of samples with a high content of unmodified DNA is provided.Keywords: tetramethylsilane, ethidium bromide, formalin, Carcinus, Lithodidae. RESUMEN: Extracción de ADN a partir de tejido fijado en formol: nueva luz desde el mar abisal. -Muestras de ADN de distintos crustáceos decápodos fueron obtenidas independientemente a partir de tejidos fijados en etanol y tejidos fijados en formol mediante un nuevo protocolo basado en el Tetrametilsilano (TMS)-Chelex. Los resultados obtenidos muestran que el ADN no se encuentra atrapado de forma irreversible en una matriz proteica y que el éxito de amplificación no depende de la extracción de inhibidores de PCR solubles. Sin embargo, nuestros resultados indican que el éxito de amplificación depende de la presencia de ADN no modificado en la muestra. Se incluye un sencillo método de tinción que facilita la identificación de muestras con un alto contenido en ADN no modificado.Palabras clave: tetrametilsilano, bromuro de etidio, formol, Carcinus, Lithodidae.

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Comparing the asymptotic power of exact tests in 2×2 tables

Cited by 21 publications

References 14 publications

Revisiting the blurry boundaries of schizophrenia: Spectrum disorders in psychometrically identified schizotypes

Revisiting the blurry boundaries of schizophrenia: Spectrum disorders in psychometrically identified schizotypes

Recommended tests for association in 2×2 tables

DNA extraction from formalin-fixed tissue: new light from the deep sea

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