Is It Really Robust?

Schmider, Emanuel; Ziegler, Matthias; Danay, Erik; Beyer, Luzi; Bühner, Markus

doi:10.1027/1614-2241/a000016

Cited by 878 publications

(358 citation statements)

References 12 publications

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“…However, when considered separately, the data within each pH level were normally distributed. Furthermore, ANOVA is known to be very robust with respect to violations of this assumption (Schmider et al, 2010), and therefore we proceeded with the analysis as planned.…”

Section: Discussionmentioning

confidence: 99%

Intra-Specific Variation Reveals Potential for Adaptation to Ocean Acidification in a Cold-Water Coral from the Gulf of Mexico

et al. 2017

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Ocean acidification, the decrease in seawater pH due to the absorption of atmospheric CO 2 , profoundly threatens the survival of a large number of marine species. Cold-water corals are considered to be among the most vulnerable organisms to ocean acidification because they are already exposed to relatively low pH and corresponding low calcium carbonate saturation states ( ). Lophelia pertusa is a globally distributed cold-water scleractinian coral that provides critical three-dimensional habitat for many ecologically and economically significant species. In this study, four different genotypes of L. pertusa were exposed to three pH treatments (pH = 7.60, 7.75, and 7.90) over a short (2-week) experimental period, and six genotypes were exposed to two pH treatments (pH = 7.60 and 7.90) over a long (6-month) experimental period. Their physiological response was measured as net calcification rate and the activity of carbonic anhydrase, a key enzyme in the calcification pathway. In the short-term experiment, net calcification rates did not significantly change with pH, although they were highly variable in the low pH treatment, including some genotypes that maintained positive net calcification in undersaturated conditions. In the 6-month experiment, average net calcification was significantly reduced at low pH, with corals exhibiting net dissolution of skeleton. However, one of the same genotypes that maintained positive net calcification (+0.04% day −1 ) under the low pH treatment in the short-term experiment also maintained positive net calcification longer than the other genotypes in the long-term experiment, although none of the corals maintained positive calcification for the entire 6 months. Average carbonic anhydrase activity was not affected by pH, although some genotypes exhibited small, insignificant, increases in activity after the sixth month. Our results suggest that while net calcification in L. pertusa is adversely affected by ocean acidification in the long term, it is possible that some genotypes may prove to be more resilient than others, particularly to short perturbations of the carbonate system. These results provide evidence that populations of L. pertusa in the Gulf of Mexico may contain the genetic variability necessary to support an adaptive response to future ocean acidification.

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Section: Discussionmentioning

confidence: 99%

Intra-Specific Variation Reveals Potential for Adaptation to Ocean Acidification in a Cold-Water Coral from the Gulf of Mexico

et al. 2017

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“…In that case, many studies have shown that for ANOVAs and t tests, departures from normality are not critical (e.g., Glass, Peckham, & Sanders, 1972;Harwell, Rubinstein, Hayes, & Olds, 1992;Lix, Keselman, & Keselman, 1996;Schmider, Ziegler, Danay, Beyer, & Bühner, 2010). For t tests, the Type I errors still meet Bradley's liberal criterion even with extreme deviations from normality, at least if the sample size is higher than about 20, if there are (approximately) equal numbers of observations per group (balanced design) and if two-tailed tests are conducted (Kubinger, Rasch, & Moder, 2009;Sawilowsky & Blair, 1992).…”

Section: Discussionmentioning

confidence: 99%

Evaluating the robustness of repeated measures analyses: The case of small sample sizes and nonnormal data

Oberfeld

Franke

2012

Behav Res

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Repeated measures analyses of variance are the method of choice in many studies from experimental psychology and the neurosciences. Data from these fields are often characterized by small sample sizes, high numbers of factor levels of the within-subjects factor(s), and nonnormally distributed response variables such as response times. For a design with a single within-subjects factor, we investigated Type I error control in univariate tests with corrected degrees of freedom, the multivariate approach, and a mixed-model (multilevel) approach (SAS PROC MIXED) with Kenward-Roger's adjusted degrees of freedom. We simulated multivariate normal and nonnormal distributions with varied population variancecovariance structures (spherical and nonspherical), sample sizes (N), and numbers of factor levels (K). For normally distributed data, as expected, the univariate approach with Huynh-Feldt correction controlled the Type I error rate with only very few exceptions, even if samples sizes as low as three were combined with high numbers of factor levels. The multivariate approach also controlled the Type I error rate, but it requires N ≥ K. PROC MIXED often showed acceptable control of the Type I error rate for normal data, but it also produced several liberal or conservative results. For nonnormal data, all of the procedures showed clear deviations from the nominal Type I error rate in many conditions, even for sample sizes greater than 50. Thus, none of these approaches can be considered robust if the response variable is nonnormally distributed. The results indicate that both the variance heterogeneity and covariance heterogeneity of the population covariance matrices affect the error rates.

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“…As these data are not normally distributed, we did not conduct any further pairwise comparisons. Since ANOVAs have shown to be robust against violations of normal distribution (Schmider et al, 2010), we do not anticipate any problems when interpreting the reported effects. Figure 8 shows the participants' flight paths and the 3.8 nm circle around the MDF VOR.…”

Section: Eye-trackingmentioning

confidence: 99%

Are pilots prepared for a cyber-attack? A human factors approach to the experimental evaluation of pilots' behavior

Gontar

Homans

Rostalski

et al. 2018

Journal of Air Transport Management

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A B S T R A C TThe increasing prevalence of technology in modern airliners brings not just advantages, but also the potential for cyber threats. Fortunately, there have been no significant attacks on civil aircraft to date, which allows the handling of these emerging threats to be approached proactively. Although an ample body of research into technical defense strategies exists, current research neglects to take the human operator into account. In this study, we present an exploratory experiment focusing on pilots confronted with a cyber-attack. Results show that the occurrence of an attack affects all dependent variables: pilots' workload, trust, eye-movements, and behavior. Pilots experiencing an attack report heavier workload and weakened trust in the system than pilots whose aircraft is not under attack. Further, pilots who experienced an attack monitored basic flying instruments less and their performance deteriorated. A warning about a potential attack seems to moderate several of those effects. Our analysis prompts us to recommend incorporating cyber-awareness into pilots' recurrent training; we also argue that one has to consider all affected personnel when designing such training. Future research should target the development of appropriate procedures and training techniques to prepare pilots to correctly identify and respond to cyber-attacks.

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Is It Really Robust?

Cited by 878 publications

References 12 publications

Intra-Specific Variation Reveals Potential for Adaptation to Ocean Acidification in a Cold-Water Coral from the Gulf of Mexico

Intra-Specific Variation Reveals Potential for Adaptation to Ocean Acidification in a Cold-Water Coral from the Gulf of Mexico

Evaluating the robustness of repeated measures analyses: The case of small sample sizes and nonnormal data

Are pilots prepared for a cyber-attack? A human factors approach to the experimental evaluation of pilots' behavior

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