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21.
Recently, there has been an increasing level of interest in subscores for their potential diagnostic value. Haberman (2008b) suggested reporting an augmented subscore that is a linear combination of a subscore and the total score. Sinharay and Haberman (2008) and Sinharay (2010) showed that augmented subscores often lead to more accurate diagnostic information than subscores. In order to report augmented subscores operationally, they should be comparable across the different forms of a test. One way to achieve comparability is to equate them. We suggest several methods for equating augmented subscores. Results from several operational and simulated data sets show that the error in the equating of augmented subscores appears to be small in most practical situations. 相似文献
22.
Sandip Sinharay 《Journal of Educational Measurement》2010,47(2):150-174
Recently, there has been an increasing level of interest in subscores for their potential diagnostic value. Haberman suggested a method based on classical test theory to determine whether subscores have added value over total scores. In this article I first provide a rich collection of results regarding when subscores were found to have added value for several operational data sets. Following that I provide results from a detailed simulation study that examines what properties subscores should possess in order to have added value. The results indicate that subscores have to satisfy strict standards of reliability and correlation to have added value. A weighted average of the subscore and the total score was found to have added value more often. 相似文献
23.
Sandip Sinharay 《Journal of Educational Measurement》2016,53(1):63-85
De la Torre and Deng suggested a resampling‐based approach for person‐fit assessment (PFA). The approach involves the use of the statistic, a corrected expected a posteriori estimate of the examinee ability, and the Monte Carlo (MC) resampling method. The Type I error rate of the approach was closer to the nominal level than that of the traditional approach of using along with the assumption of a standard normal null distribution. This article suggests a generalized resampling‐based approach for PFA that allows one to employ or another person‐fit statistic (PFS) based on item response theory, the corrected expected a posteriori estimate or another ability estimate, and the MC method or another resampling method. The suggested approach includes the approach of de la Torre and Deng as a special case. Several approaches belonging to the generalized approach perform very similarly to the approach of de la Torre and Deng's in two simulation studies and in applications to three real data sets, irrespective of the PFS used. The generalized approach promises to be useful to those interested in resampling‐based PFA. 相似文献
24.
Pakrashi Anita Pandit Srikanta Bandyopadhyay Sandip K. Pakrashi Satyesh C. 《Indian journal of clinical biochemistry : IJCB》2003,18(1):15-21
Post-treatment of the indomethacin induced ulcerated rats at the optimal dose of 100 mg/kg body-wt. orally for 7 consecutive
days with the lyophilized aqueous extract of the fruits ofPhyllanthus emblica L. syn.Emblica officinalis Gaertn. (Euphorbiaceae) exhibited highly significant (p<0.001) enhancement of secretion of catalase, reduced glutathione
and decrease in malonyldialdehyde (MDA). Furthermore, the gross morphological observation and highly significant (p<0.001)
decrease of ulcer index (81.43%) indicated healing effect of the extract on gastric ulcer. 相似文献
25.
Indranil Chakraborty Sanjoy Kunti Mousumi Bandyopadhyay Anindya Dasgupta Gopal Deb Chattopadhyay Sandip Chakraborty 《Indian journal of clinical biochemistry : IJCB》2007,22(2):109-113
An imbalance in the systemic redox status leading to oxidative stress has been an important factor in development of senile
cataracts, which is reflected by an increase in serum TBARS and a decrease in plasma SOD activity. Zinc has been an important
cofactor required for structural stability of SOD. In the present study the role of serum zinc level and plasma SOD activity
was analyzed in senile cataract patients showing significant oxidative stress. Serum TBARS, plasma SOD and serum zinc level
was measured in thirty randomly selected senile cataract patients against properly matched controls. Although, the analysis
of means showed a significant increase in serum TBARS and decrease in plasma SOD and serum zinc level in cases, but plasma
SOD was found to be just significantly correlated (p=0.05) with the serum zinc only in the cases. The results of partial correlation
studies and multiple regression analysis, also, showed only a significant correlation and predictable dependence between serum
TBARS and plasma SOD, excluding any role of serum zinc level. The present study concludes that it is chiefly the plasma SOD
activity, but not the serum zinc level, that determines the proneness of the patients for development of senile cataract. 相似文献
26.
Babul Bandyopadhyay Sandip K Bandyopadhyay 《Indian journal of clinical biochemistry : IJCB》1998,13(1):41-45
Prostaglandins and (PG) have been reported to be an important gastric acid suppressive factor. However, the mechanism underlying
is yet to be clearly established. In vitro study with gastric microsomes in presence of both PGE2 and PGI2 shows a stimulation of gastric H+ K+-ATPase activity below 1X10−6M and 2.5X10−7M concentrations respectively. However, with further increase in concentrations of both PGE2 and PGI2, H+, K+-ATPase activity shows an inhibition but PGI2 completely obliterates the K+ stimulated part of H+, K+-ATPase activity at higher concentration. The H+-ion transport study using chambered frog gastric mucosa shows that both PGE2 and PGI2 inhibit H+-ion transport at 5X10−6 M and 10X10−6M concentrations respectively but the effect of PGI2 is reversible. These differential effects of PGE2 and PGI2 on microsomal H+, K+-ATPase and on H+ transport my be caused by the differential effects of these phospholipid mediators with the gastric mucosal cell membrane.
This in vitro investigation shows the role of prostaglandin (s) as a physiological switch/regulator of gastric H+ ion transport leading to the cessation of gastric acid secretion. 相似文献
27.
Standard 3.9 of the Standards for Educational and Psychological Testing ( 1999 ) demands evidence of model fit when item response theory (IRT) models are employed to data from tests. Hambleton and Han ( 2005 ) and Sinharay ( 2005 ) recommended the assessment of practical significance of misfit of IRT models, but few examples of such assessment can be found in the literature concerning IRT model fit. In this article, practical significance of misfit of IRT models was assessed using data from several tests that employ IRT models to report scores. The IRT model did not fit any data set considered in this article. However, the extent of practical significance of misfit varied over the data sets. 相似文献
28.
Sandip Sinharay 《Educational Measurement》2018,37(2):64-69
The choice of anchor tests is crucial in applications of the nonequivalent groups with anchor test design of equating. Sinharay and Holland (2006, 2007) suggested “miditests,” which are anchor tests that are content‐representative and have the same mean item difficulty as the total test but have a smaller spread of item difficulties. Sinharay and Holland (2006, 2007), Cho, Wall, Lee, and Harris (2010), Fitzpatrick and Skorupski (2016), Liu, Sinharay, Holland, Curley, and Feigenbaum (2011a), Liu, Sinharay, Holland, Feigenbaum, and Curley (2011b), and Yi (2009) found the miditests to lead to better equating than minitests, which are representative of the total test with respect to content and difficulty. However, these findings recently came into question as Trierweiler, Lewis, and Smith (2016) concluded, based on a comparison of correlation coefficients of miditests and minitests with the total test, that making an anchor test a miditest does not generally increase the anchor to total score correlation and recommended the continuation of the practice of using minitests over miditests. Their recommendation raises the question, “Should miditests continue to be considered in practice?” This note defends the miditests by citing literature that favors miditests and then by showing that miditests perform as well as the minitests in most realistic situations considered in Trierweiler et al. (2016), which implies that miditests should continue to be seriously considered by equating practitioners. 相似文献
29.
Feinberg and Wainer (2014) provided a simple equation to approximate/predict a subscore's value. The purpose of this note is to point out that their equation is often inaccurate in that it does not always predict a subscore's value correctly. Therefore, the utility of their simple equation is not clear. 相似文献
30.
Sandip Sinharay 《Educational Measurement》2013,32(4):38-42
Brennan ( 2012 ) noted that users of test scores often want (indeed, demand) that subscores be reported, along with total test scores, for diagnostic purposes. Haberman ( 2008 ) suggested a method based on classical test theory (CTT) to determine if subscores have added value over the total score. According to this method, a subscore has added value if the corresponding true subscore is predicted better by the subscore than by the total score. In this note, parallel‐forms scores are considered. It is proved that another way to interpret the method of Haberman is that a subscore has added value if it is in better agreement than the total score with the corresponding subscore on a parallel form. The suggested interpretation promises to make the method of Haberman more accessible because several practitioners find the concept of parallel forms more acceptable or easier to understand than that of a true score. Results are shown for data from two operational tests. 相似文献