Latent variable

Robust calibration of option valuation models to quoted option prices is non-trivial but crucial for good performance. A framework based on the state-space formulation of the option valuation model is introduced. Non-linear (Kalman) filters are needed to do inference since the models have latent variables (e.g. volatility). The statistical framework is made adaptive by introducing stochastic dynamics for the parameters. This allows the parameters to change over time, while treating the measurement noise in a statistically consistent way and using all data efficiently. The performance and computational efficiency of standard and iterated extended Kalman filters (EKF and IEKF) are investigated. These methods are compared to common calibration such as weighted least squares (WLS) and penalized weighted least squares (PWLS). A simulation study, using the Bates model, shows that the adaptive framework is capable of tracking time varying parameters and latent processes such as stochastic ...

In the literature about category effects in semantic memory, body parts and musical instruments are often considered atypical, because in cases with a disproportionate impairment of living categories body parts are relatively spared, while musical instruments are often severely defective. In this study the performance of 57 subjects affected by diseases generally associated with lexical-semantic impairment, for the most part

The present study utilized a latent variable modeling approach to examine the Simple View of Reading in a sample of students from 3rd, 7th, and 10th grades (N = 215, 188, and 180, respectively). Latent interaction modeling and other latent variable models were employed to investigate (a) the functional form of the relationship between decoding and linguistic comprehension in third grade, (b) the contribution of these predictors as children progress through school, and (c) the contribution of passage fluency, working memory, and performance IQ to a model of reading for all grades. Results did not support the Simple View of Reading for students in grades 3, 7 and 10. Additionally, it was found that passage fluency significantly predicted reading comprehension after controlling for decoding and linguistic comprehension for students in grades 7 and 10. Likewise performance IQ was found to be a significant predictor of reading comprehension for students in third grade.

This paper presents a structural model of the determinants of harsh parenting among Mexican mothers. One hundred five mothers (46 from the community; 59 referred to agencies for child maltreatment) were recruited from Sonora (Northern) Mexico and interviewed. In this model the use of physical punishment was explained by (1) authoritarian parenting style (mothers' beliefs concerning the effective use of physical punishment and mothers' lack of disciplinary skills) and (2) family dysfunction (a latent variable constructed from reports of interspousal violence and the parents' use of alcohol and drugs). In addition, the indirect effects of demographic and historical variables on harsh parenting was included. The findings show that the most important factor influencing the use of physical punishment in these families was authoritarian parenting style, exerting a significant direct effect on the mothers' reports of their use of harsh punishment. Family dysfunction had an indirect effect through parenting style. Some sociodemographic variables also indirectly influenced the use of beliefs maternal punishment It is concluded that cultural beliefs play a major role in parenting within the framework of Mexican family relations.

Abstract: The rapid growth of e-commerce is imposing profound impacts on modern society. On the supply side, the emergence of e-commerce is greatly changing the operation behavior of some retailers and is increasing product internationalization due to its geographically unlimited nature. On the demand side, the pervasiveness of e-commerce affects how, where, and when consumers shop, and indirectly influences the way in which we live our lives. However, the development of ecommerce is still in an early stage, and ...

The innovative performance of companies has been studied quite extensively and for a long period of time. However, the results of many studies have not yet led to a generally accepted indicator of innovative performance or a common set of indicators. So far the variety in ...

Sex differences in the latent general and broad cognitive abilities underlying the Woodcock–Johnson Tests of Cognitive Abilities were investigated for children, youth, and adults ages 6 through 59. A developmental, multiple indicator–multiple cause, structural equation model was used to investigate sex differences in latent cognitive abilities as well as developmental changes in these differences across the 6 to 59 age span. Females showed a consistent advantage on the latent processing speed (Gs) factor, and males showed a small, consistent advantage on the latent comprehension–knowledge (Gc) factor. Males also showed an advantage on latent quantitative reasoning (RQ) and visual–spatial ability (Gv) factors at most ages, although the latter was statistically significant only for adults. No statistically significant sex differences were shown on latent auditory processing, short-term memory, long-term retrieval, or fluid reasoning factors. The higher-order, latent g factor showed inconsistent differences for children, small, non-significant differences favoring females for adolescents, and fairly consistent statistically significant differences favoring females in adulthood. Findings are inconsistent with developmental theory that suggests males should show an advantage on g in adulthood. Supplemental analyses suggested that methodological choices, including the use of latent variables versus composites and methods for dealing with missing data, can affect research findings.