Equivalence tests – A review

Meyners, Michael

doi:10.1016/j.foodqual.2012.05.003

Cited by 111 publications

(108 citation statements)

References 57 publications

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“…) and for use in equivalence testing (c.f. Castura ; Meyners ). Also, we have assumed a unidimensional structure – a multidimensional examination of the test such as appears in Ennis and Mullen () for the Triangle test, could also prove helpful.…”

Section: Resultsmentioning

confidence: 99%

AThurstonian Analysis of theTwo‐Out‐of‐Five Test

Ennis

2013

Journal of Sensory Studies

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The Two‐Out‐of‐Five test is a method of unspecified difference testing. Although its low guessing probability (1/10) gives promise that it might have high power, the theoretical underpinnings of the method have not yet been investigated. In this article, we offer the first such investigation, via Thurstonian analysis. This investigation reveals that the standard form of the Two‐Out‐of‐Five test is more statistically powerful than the Triangle test, but not as powerful as the Tetrad test. We then propose a new way of scoring Two‐Out‐of‐Five data that yields a test with higher power and lower sample size requirements than the Tetrad test, under the assumption that there is no additional noise from the evaluation of an additional stimulus. This last result is achieved without any experimental modification of the Two‐Out‐of‐Five protocol. Tables for estimating the Thurstonian measure of sensory effect size, δ, for calculating the error in such estimates, and for recommended sample sizes are given. Finally, caution is given against incorrect instructions in the Two‐Out‐of‐Five test – if respondents are asked simply to identify the two most similar samples, the resulting test has almost no power. Practical Applications This article shows that the standard form of the Two‐Out‐of‐Five test is more powerful than the Triangle test, but is not as powerful as the Tetrad test. The article then proposes a new method of scoring Two‐Out‐of‐Five data that requires smaller sample sizes than the Tetrad test, under the assumption that the evaluation of an additional stimulus does not lead to an increase in perceptual noise. When this alternate method of scoring the data is used, the test is called the Two‐Out‐of‐Five test with forgiveness. Tables for estimating δ, the Thurstonian measure of sensory difference, together with B values that allow practitioners to calculate the variance in their estimates are given for both forms of the Two‐Out‐of‐Five test. Tables of recommended sample sizes are also given in each case. Finally, it is noted that care must be taken to give correct instructions to respondents – it is possible to create a test with very low power if respondents are simply asked to identify the two most similar stimuli.

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Section: Resultsmentioning

confidence: 99%

AThurstonian Analysis of theTwo‐Out‐of‐Five Test

Ennis

2013

Journal of Sensory Studies

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“…In comparison with the control, fewer bacterial communities were found in HHP-treated samples. Entero bacteriaceae, gram-negative bacteria, are generally less resistant to HHP than gram-positive bacteria (19,36). Therefore, they were not detected in the HHP-treated samples.…”

Section: Resultsmentioning

confidence: 99%

Impact of High Hydrostatic Pressure Treatment on Microbial Communities in Chinese Water-Boiled Salted Duck

Feng

Wang

et al. 2014

Journal of Food Protection

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The objective of this study was to determine the impact of high hydrostatic pressure (HHP) treatment on microbial communities in Chinese water-boiled salted duck (CWBSD) and the synergistic effect of HHP and mild heat treatment. In this work, the bacterial diversity was evaluated by using both a culture-dependent method and denaturing gradient gel electrophoresis. The total aerobic bacterial counts in pressure-treated samples were significantly lower than those in controls, which indicated that HHP could extend the shelf life of CWBSD. Weissella hellenica and Enterobacteriaceae, the predominant bacteria found in CWBSD, were not detected after HHP treatment. On the other hand, Staphylococcus spp. and Bacillus spp. became the predominant bacteria in HHP-treated samples. Moreover, the inhibitory effect was greater at 400 MPa than at 200 MPa combined with mild heat at 40°C. This study investigated the diversity of bacteria in HHP-treated CWBSD, and the information derived from this research may help to understand the bacterial ecology and develop effective HHP treatments to extend the shelf life of CWBSD.

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“…Aplicouse, então, o two one-sided test (TOST) [22], para o qual define-se um intervalo entre δ 1 e δ 2 e aplica-se dois testes de hipótese. Para que os dados sejam equivalentes, as hipóteses nulas H 0a (μ≤δ 1 ) e H 0b (μ≥δ 2 ) devem ser rejeitadas.…”

Section: Resultsunclassified