摘要:

This article presents a study of hitting streaks for individual batters in the game of baseball. All baseball fans know that players go through periods where they never seem to make an out and other periods where nothing will get them to base. There is no doubt that “hot streaks” and “cold streaks” do occur. The question explored here is whether these streaks occur more (or less) frequently than would be predicted by a probabilistic model of randomness. I examined the records of many “regular” Major League players through four seasons, 1987–1990 and used several statistical methods to check for streakiness. These include standard methods such as the runs test, as well as a more complex logistic regression model with several explanatory variables. Based on all of these methods, there is no doubt that a certain number of players exhibited definite streakiness in certain years. But the evidence also suggests that the behavior of all players examined, taken as a whole, does not differ significantly from what would be expected under a model of randomness. Furthermore, none of the players examined in the study exhibited unusually streaky behavior over the entire four-year period.

ISSN:0162-1459    

DOI:10.1080/01621459.1993.10476395

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0162-1459    

DOI:10.1080/01621459.1993.10476396

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0162-1459    

DOI:10.1080/01621459.1993.10476397

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0162-1459    

DOI:10.1080/01621459.1993.10476398

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

When respondents to sample surveys differ from nonrespondents, bias can result. Nonresponse is produced by both refusal and nonavailability. Here we concentrate on nonavailability. Clever weighting schemes to deal with nonavailability bias were proposed about 40 years ago by Politz and Simmons and by Simmons, but further theoretical development has been limited. In the meantime, not only have in-person surveys continued to flourish, but telephone surveys also have become common. Herein we present weighting techniques that correct for nonavailability bias yet avoid limitations of earlier methods. The weights (which depend on parameters) are based on the number of callbacks needed to obtain the interview from the sample member, and usually increase with the number of callbacks. If a sample design generated sample weights that are not all the same, those external weights are easily incorporated into the analysis. We assume a beta distribution forp, the probability or proportion of time that a sample member is available for interview. The conditional expectation of the response variable givenpis assumed to be a linear (or other) function ofp. Our simplest callback model, suitable for some telephone surveys, requires estimates of the two parameters of the beta distribution. Two other models, designed for surveys where interviewers use cues to infer the best times for callbacks, each have a third parameter. For a number of published empirical callback distributions (most with truncation or censoring), parameters under the different models are estimated and the results evaluated.

ISSN:0162-1459    

DOI:10.1080/01621459.1993.10476399

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Using administrative records on earnings, hours worked, and hourly wages for hourly employees of a single manufacturing firm, we found standard assumptions about errors in survey measures to be violated to varying extents. Errors are correlated with true scores, and errors in reports of earnings and hours in different periods are generally positively correlated with one another, particularly for reports given in a single interview. Although a high proportion of reporting errors are from an approximately normal distribution, a small proportion comes from a distribution with a much greater variance, and these cases often have considerable influence on estimates of relationships between variables.

ISSN:0162-1459    

DOI:10.1080/01621459.1993.10476400

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

We apply hazard function models to marketing data on household purchases of disposable diapers to calibrate repeat-purchase and brand-switching behaviors. In the model we allow for household-specific unobserved traits. Hazard function models with fixed-effects heterogeneity specification are computationally feasible. We directly compare the results of fixed- and random-effects heterogeneity specifications in the context of parametric and nonparametric duration-dependence functions. We find that a rigorous test fails to reject the random-effects specification in favor of the fixed-effects specification. The unimodal gamma distribution in the random-effects specification adequately captures unobserved heterogeneity.

ISSN:0162-1459    

DOI:10.1080/01621459.1993.10476401

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A method for modeling a changing periodic pattern is developed. The use of time-varying splines enables this to be done relatively parsimoniously. The method is applied in a model used to forecast hourly electricity demand, with the periodic movements being intradaily or intraweekly. The full model contains other components, including a temperature response, which is also modeled using splines.

ISSN:0162-1459    

DOI:10.1080/01621459.1993.10476402

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A Bayesian nonparametric view of compliance to occupational standards is achieved through predictive distributions. The common assumption of lognormality of environmental exposures is relaxed while recognizing the practicality of a finite number of possible samples. These probability of compliance calculations are conditional on observing some of the samples. Familiar binomial and normal modes are identified with the classical perspective as limits of Bayesian nonparametric and parametric strategies, when the number of observed samples increases. In this situation, extensive previous sample data provide a correspondence between the classical and Bayesian approaches, rather than little or no previous information. Using an example, alternative procedures are illustrated and compared. Currently used methodology can be anti-conservative for protecting employees.

ISSN:0162-1459    

DOI:10.1080/01621459.1993.10476403

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The Fisher and Neyman-Pearson approaches to testing statistical hypotheses are compared with respect to their attitudes to the interpretation of the outcome, to power, to conditioning, and to the use of fixed significance levels. It is argued that despite basic philosophical differences, in their main practical aspects the two theories are complementary rather than contradictory and that a unified approach is possible that combines the best features of both. As applications, the controversies about the Behrens-Fisher problem and the comparison of two binomials (2 × 2 tables) are considered from the present point of view.

ISSN:0162-1459    

DOI:10.1080/01621459.1993.10476404

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor