Approach For Testing Hypotheses Research Articles

COMPARATIVE ANALYSIS OF THE BEHAVIOR OF RUSSIAN HIGH-TECH AND LOW-TECH MANUFACTURING COMPANIES

The high-tech sector is considered to be innovatively active, but its contribution to GDP does not change, despite the measures taken by the government. This may be due to the same behavior patterns of high- and low-tech companies. The analysis of the behavior of high- and low-tech companies was carried out according to the data of surveys of heads of domestic manufacturing enterprises. The approach for testing hypotheses about possible differences in the behavior of high- and low-tech companies in different economic conditions is based on a statistical comparison of the average values of indicators for companies in these sectors. It was found that the level of innovation activity among high-tech companies declines to a lesser extent than among low-tech companies during the crisis. In these conditions, high-tech companies are more actively using "internal reserves": they are working more to improve the skill level of staff and implementing innovation processes. During periods of high and low rates of economic growth, high-tech companies often buy new technology. The rest of the patterns of behavior of high- and low-tech companies do not differ.

(1909-5487) Fuzzy decision in testing hypotheses by fuzzy data: Two case studies

In testing hypotheses, we may confront to cases where data are recorded as non-precise (fuzzy) rather than crisp. In such situations, the classical methods of testing hypotheses are not capable and need to be generalized. In solving theproblem of testing hypotheses based on fuzzy data, the fuzziness of the observed data leads to the fuzzy p-value. This paper has been focused to calculate fuzzy p-value based on fuzzy data using the extension principle. Also, consideringthat p-value method is the most widely used / popular approach for testing hypotheses among different sciences users, two fuzzy p-value-based case studies have been provided in this paper. The first case study is discussed on “the fuzzydata from a speedometer camera” and the second is deliberate about “the lifetime of produced batteries in a factory” and both of them have been solved by a novel approach considering other studies found in the literature.

Testing Hypotheses Of Covariance Structure In Multivariate Data

In this paper there is given a new approach for testing hypotheses on the structure of covariance matrices in double multivariate data. It is proved that ratio of positive and negative parts of best unbiased estimators (BUE) provide an F-test for independence of blocks variables in double multivariate models.

The Effect of Scale Referent on Tests of Mean Structure Parameters

ABSTRACTStructured means analysis is a very useful approach for testing hypotheses about population means on latent constructs. In such models, a z test is most commonly used for testing the statistical significance of the relevant parameter estimates or of the differences between parameter estimates, where a z value is computed based on the asymptotic standard error estimate associated with the parameter of interest. In the current article, a series of population analyses demonstrate that the z tests for latent mean structure parameters or, more directly, the standard error estimates upon which those z tests are based are, not invariant to how factors are scaled. As such, circumstances exist in which latent mean inference is compromised solely as a result of scaling decisions. This problem is illustrated in the context of between-subjects (i.e., multisample) latent means models and within-subjects latent means models. Recommendations for practice are also offered.

Statistical Models of the Troposphere Refractive Index

The statistical model for describing the refractive index of the troposphere based on nested semi-Markov processes is proposed. The possibility of describing the statistics of the refractive index in season by locally Gaussian model is shown. First considered the use of atomic functions (AF) to describe the statistics of the refractive index, a new approach for testing hypotheses about the form of the random variable, based on the use of inverse functions is proposed.

Bayesian and Classical Approaches for Hypotheses Testing in Trisomies

We introduce classical approaches for testing hypotheses on the meiosis I non disjunction fraction in trisomies, such as the likelihood-ratio, bootstrap, and Monte Carlo procedures. To calculate the p-values for the bootstrap and Monte Carlo procedures, different transformations in the data are considered. Bootstrap confidence intervals are also used as a tool to perform hypotheses tests. A Monte Carlo study is carried out to compare the proposed test procedures with two Bayesian ones: Jeffreys and Pereira-Stern tests. The results show that the likelihood-ratio and the Bayesian tests present the best performance. Down syndrome data are analyzed to illustrate the procedures.

Supplemental Material for A Generally Robust Approach for Testing Hypotheses and Setting Confidence Intervals for Effect Sizes

Supplemental Material for A Generally Robust Approach for Testing Hypotheses and Setting Confidence Intervals for Effect Sizes

Bioinformatics models in drug abuse and Neuro-AIDS: Using and developing databases.

The magnitude of the problems of drug abuse and Neuro-AIDS warrants the development of novel approaches for testing hypotheses in diagnosis and treatment ranging from cell culture models to developing databases. In this study, cultured neurons were treated with/without HIV-TAT, ENV, or cocaine in a 2x2x2 expression study design. RNA was purified, labeled, and expression data were produced and analyzed using ANOVA. Thus, we identified 35 genes that were significantly expressed across treatment conditions. A diagram is presented showing examples of molecular relationships involving a significantly expressed gene in the current study (SOX2). Also, we use this information to discuss examples of gene expression interactions as a means to portray significance and complexity of gene expression studies in Drug Abuse and Neuro-AIDS. Furthermore, we discuss here that critical interactions remain undetected, which may be unravelled by developing robust database systems containing large datasets and gleaned information from collaborating scientists . Hence, we are developing a public domain database we named The Agora database , that will served as a shared infrastructure to query, deposit, and review information related to drug abuse and dementias including Neuro-AIDS. A workflow of this database is also outlined in this paper.

USING COALESCENT SIMULATIONS TO TEST THE IMPACT OF QUATERNARY CLIMATE CYCLES ON DIVERGENCE IN AN ALPINE PLANT-INSECT ASSOCIATION

The Quaternary climate cycles forced species to repeatedly migrate across a continually changing landscape. How these shifts in distribution impacted the evolution of unrelated but ecologically associated taxa has remained elusive due to the stochastic nature of the evolutionary process and variation in species-specific biological characteristics and environmental constraints. To account for the uncertainty in genealogical estimates, we adopted a coalescent approach for testing hypotheses of population divergence in coevolving taxa. We compared genealogies of a specialized herbivorous insect, Parnassius smintheus (Papilionidae), and its host plant, Sedum lanceolatum (Crassulaceae), from the alpine tundra of the Rocky Mountains to null distributions from coalescent simulations to test whether tightly associated taxa shared a common response to the paleoclimatic cycles. Explicit phylogeographic models were generated from geologic and biogeographic data and evaluated over a wide range of divergence times given calibrated mutation rates for both species. Our analyses suggest that the insect and its host plant responded similarly but independently to the climate cycles. By promoting habitat expansion and mixing among alpine populations, glacial periods repeatedly reset the distributions of genetic variation in each species and inhibited continual codivergence among pairs of interacting species.

Genetic manipulation of noradrenergic neurons.

The neurotransmitter norepinephrine has been the focus of intense investigation for nearly a century. With advances in technology come novel approaches for testing hypotheses about the physiological roles of norepinephrine and the genes involved in norepinephrine (NE) biosynthesis, metabolism, and noradrenergic signaling. Homologous recombination techniques, which generate mice deficient in specific gene products, aid the integrated physiologist and pharmacologist in the evaluation of protein function. Mouse models lacking proteins involved in NE biosynthesis or metabolism provide tools to expand the knowledge previously gleaned from pharmacologic studies. Removal of the biosynthetic enzymes tyrosine hydroxylase and dopamine-beta-hydroxylase yield animals deficient in norepinephrine and have been used to further examine the role of NE in diverse physiologic roles. Complete removal of the vesicular monoamine transporter has demonstrated that mobilizing neurotransmitters to vesicles is required for animal survival. Lastly, the generation of animals in which the ability to remove NE from the synapse is impaired (norepinephrine transporter deficiency and extraneuronal monoamine transporter deficiency) and in which the enzymes responsible for the metabolism of NE have been removed (catechol-O-methyltransferase and monoamine oxidase) has facilitated the study of the long-term physiological consequences of altered NE homeostasis.

Subadult Plumage in the House Finch and Tests of Models for the Evolution of Delayed Plumage Maturation

-In many passerine species males do not attain definitive breeding plumage until after their first potential breeding season. Such delayed plumage maturation has been the subject of numerous studies, most of which have focused on the adaptive value of femalelike plumage for young males in single populations. Thus, although studies of delayed plumage maturation have been presented as tests of evolutionary hypotheses, most have lacked an appropriate comparative perspective. Moreover, most studies of subadult plumage in passerines have been conducted without information on the general function of ornamental plumage in the species being studied. A study of delayed plumage maturation in the House Finch (Carpodacus mexicanus) provided an opportunity to overcome these problems. The function and proximate control of ornamental plumage coloration in House Finches have been studied extensively. In addition, House Finches occupy a wide range across North America with approximately 15 subspecies recognized, and populations vary in expression of delayed plumage maturation. In most populations, including the most familiar subspecies, C. m. frontalis, males acquire definitive basic plumage in their first prebasic molt. In at least three populations, C. m. griscomi of southern Mexico, C. m. amplus of Guadalupe Island, and Great Basin populations of C. m. frontalis, however, males do not acquire definitive plumage until the completion of their second prebasic molt, spending their first potential breeding season in a female-like plumage. Using a composite phylogeny and parsimony analysis, I show that delayed plumage maturation likely was lost in the ancestral House Finch population and was regained independently by the three taxa in which it is now observed. Thus, delayed plumage maturation in the House Finch is a derived trait. In addition, I show that the acquisition of delayed plumage maturation is associated with a reduction in the extent of ornamental plumage (i.e. a reduction in patch size). These observations support the idea that delayed plumage maturation in the House Finch is an adaptation to increased production costs of red ornamental display plumage in some populations. Received 28 November 1995, accepted 25 April 1996. DELAYED PLUMAGE MATURATION describes a developmental pattern generally limited to males, whereby individuals do not acquire definitive breeding plumage until after their first potential breeding season (Rohwer et al. 1980, Rohwer and Butcher 1988). Studies of delayed plumage maturation most frequently concern Temperate Zone passerines that spend only one potential breeding season in a subadult plumage (Rohwer and Butcher 1988, Butcher and Rohwer 1989, Zack and Stutchbury 1992). Despite a substantial literature on delayed plumage maturation (see Zack and Stutchbury 1992), our understanding has advanced relatively little since interest in the topic was first ignited by Rohwer et al. (1980). I believe that the ma1 E-mail: geoffrey.hill@ag.auburn.edu jority of research on delayed plumage maturation in passerines suffers from two fundamental problems: (1) lack of a general understanding of the function of ornamental plumage coloration, and (2) lack of an appropriate comparative approach to testing hypotheses for the evolution of delayed plumage maturation. The first of these problems clearly is a case of putting the cart before the horse. Ornamental plumage coloration, either bright structural coloration, bright carotenoid-based coloration, or highly contrasting melanin-based coloration, is universally assumed to function as a signal in avian communication (Butcher and Rohwer 1989). Signaling generally is believed to occur in the context of either intersexual or intrasexual interactions (Butcher and Rohwer 1989), but predator-prey interactions also have been considered (Gotmark 1992, 1993). An assump-

A New Approach to Studying Modern Human Origins: Hypothesis Testing with Coalescence Time Distributions

A new approach for testing hypotheses about modern human origins using molecular divergence dates is presented. Coalescence times from many unlinked loci are needed to test the alternative models. Hypotheses are evaluated on the basis of their differing predicted distribution patterns of coalescence times from multiple genes. No single coalescence time from one genetic system is sufficient to reject any of the three alternative models. Several nuclear datasets give recent dates for human genetic ancestors, at approximately the mitochondrial coalescence time, while some nuclear datasets support older dates. Given the overall distribution of available mitochondrial and nuclear coalescence times, the rapid replacement hypothesis is the likeliest model for modern human origins. The unusual nature of the human mitochondrial pattern is highlighted by comparative data from nonhuman hominoids. To understand the pattern of modern human genetic variability better, more nuclear data from all hominoid species are needed.

A Note on the Multivariate General Linear Test

Abstract The general linear test approach for testing hypotheses concerning parameters of a full-rank multivariate regression model is often not sufficiently discussed in applied multivariate analysis textbooks. This note makes mention of this approach and suggests that major emphasis of this topic in an applied multivariate analysis course provides students with a unifying structure for the analysis of statistical models.