Testing the Statistical Certainty of a Response to Increasing Doses of a Drug

Biometrics ◽  
1985 ◽  
Vol 41 (1) ◽  
pp. 295 ◽  
Author(s):  
J. W. Tukey ◽  
J. L. Ciminera ◽  
J. F. Heyse
2001 ◽  
Vol 84 (5) ◽  
pp. 1534-1542 ◽  
Author(s):  
Stefania Vichi ◽  
Lorena Pizzale ◽  
Emilio Toffano ◽  
Renzo Bortolomeazzi ◽  
Lanfranco Conte

Abstract Free sterols were evaluated as factors for discriminating between genuine virgin olive oil and hazelnut-mixed virgin olive oil. Numeric analyses of the results amplified the differences between groups. The application of this method to virgin olive oil samples and their mixtures with 10% hazelnut oil distinguished between genuine and nongenuine virgin olive oil with statistical certainty. Triacylglycerol analysis was tested for the same purpose by using parameter ΔECN42, but although it possessed a discriminating capacity, it alone could not distinguish the aforementioned groups with sufficient certainty. Free Δ7-sterols data were combined with ΔECN42 data into a single discriminating function to improve differentiation and bring more ruggedness, and for detection of low amounts (10%) of hazelnut oil in virgin olive oil. In fact, the values obtained by addition of Δ7-sterol data and ΔECN42 data showed a higher discriminating capacity than single parameters. In a single operation the method produced all the oil fractions necessary for analysis of free sterols and triacylglycerols with ECN42. Solid-phase extraction was applied in substitution of traditional chromatography on a silica column.


1989 ◽  
Vol 30 (1) ◽  
pp. 65-68 ◽  
Author(s):  
B. Danielson ◽  
K. Frennered ◽  
G. Selvik ◽  
L. Irstam

Different degrees of artificial L5-SI spondylolisthesis were created using a lumbar specimen. Lateral radiographs were obtained of each, with the specimen tilted and/or rotated. The true spondylolisthesis was determined stereophotogrammetrically. The slip, measured on the radiographs, was calculated according to two methods modified from Boxall et coll. (2). No significant difference in accuracy was found between these two methods. The difference in calculated slip between examinations needs to be at least 20 per cent of the sagittal length of L5 to be regarded as a true progression. A true progress of slip of less than 20 per cent is difficult to detect with statistical certainty.


1980 ◽  
Vol 35 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Karl-Heinz Tytko ◽  
Georgios Petridis ◽  
Bernd Schönfeld

The system H+/MoO42- was investigated by Raman spectroscopy in the range Z = 0 to 1.14 at initial concentrations CMoO₄ 2- = 0.02 to 2M and concentrations of the ionic medium CMe+ = 2CMoO₄ 2- to 3M Me(Cl,NO3) (Me=Li, Na, K,NH4 , Mg/2). The mole-ratio method and intensity difference diagrams do not indicate any species between MoO42- and Mo7O246- contrary to propositions in recent papers. A detailed evaluation of the extensive data shows the possible portion of such species to be < 3 % , this value having a statistical certainty of 95%. Comparing the solutions having Z = 1.1 by fingerprint procedures, in all cases Mo7O246- is the first main product (detectable by static methods) irrespective of the nature and concentration of the ionic medium. Thus, Mg2+ ions do not influence the course of aggregation of molybdate ions as has been proposed in the literature. This is in accordance with theoretical investigations since the Mo7O246- ion has the distinction of a number of favourable structural parameters in the system that become operative in case of scarcity of H+ ions.


Author(s):  
Angel Fernando Kuri-Morales

The exploitation of large databases implies the investment of expensive resources both in terms of the storage and processing time. The correct assessment of the data implies that pre-processing steps be taken before its analysis. The transformation of categorical data by adequately encoding every instance of categorical variables is needed. Encoding must be implemented that preserves the actual patterns while avoiding the introduction of non-existing ones. The authors discuss CESAMO, an algorithm which allows us to statistically identify the pattern preserving codes. The resulting database is more economical and may encompass mixed databases. Thus, they obtain an optimal transformed representation that is considerably more compact without impairing its informational content. For the equivalence of the original (FD) and reduced data set (RD), they apply an algorithm that relies on a multivariate regression algorithm (AA). Through the combined application of CESAMO and AA, the equivalent behavior of both FD and RD may be guaranteed with a high degree of statistical certainty.


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