No description available.

Volatiles of peach (Prunus persica L., cultivar, Gleason Early Elberta) fruit were studied by gas-liquid chromatography, thin-layer chromatography, and infrared spectrometry. Hard mature, firm mature, soft mature, tree ripe, and artificially ripened hard mature fruit obtained from four seasons, 1964 to 1967, were used. A total of 86 peaks were observed in the chromatogram of the tree ripe peach volatiles. Major components of the volatiles identified were mainly esters, gamma and delta lactones, aldehydes, alcohols, and terpenes. In general, concentration of the volatile components were found to increase with the maturity of the fruit. However, that of the artificially ripened fruit did not reach the same level of the tree ripe fruit.

Quantile Regression, as introduced by Koenker, R. and Bassett, G. (1978), provides a complete picture of the relationship between the response variable and covariates by estimating a family of conditional quantile functions. Also, it offers a natural solution to challenges such as; homoscedasticity and sometimes unrealistic normality assumption in the usual conditional mean regression. Most of the results for quantile regression are based on simple random sampling (SRS). In this thesis, we study the quantile regression with rank-based sampling methods. Rank-based sampling methods have a wide range of applications in medical, ecological and environmental research, and have been shown to perform better than SRS in estimating several population parameters. We propose a new objective function which takes into account the ranking information to estimate the unknown model parameters based on the maxima or minima nomination sampling designs. We compare the mean squared error of the proposed quantile regression estimates using maxima (or minima) nomination sampling design and observe that it provides higher relative e ciency when compared with its counterparts under SRS design for analyzing the upper (or lower) tails of the distribution of the response variable. We also evaluate the performance of our proposed methods when ranking is done with error. / February 2017

Göttingen, Universiẗat, Diss., 2003. / Dateien in unterschiedlichen Formaten.

The intent of this thesis is to investigate, develop, and apply techniques to determine the reliability and maintainability of populations of items. These techniques are to be used in determining the total life-time operating costs of the populations so that those items with the lowest life-time costs can be bought. To do this, the author has explored current techniques for determining compliance to some minimum required Mean Time Between Failure (MTBF) in what is referred to as a Phase I testing. After the requirements of Phase I testing have been met, testing may be continued at the option of the contractor and confidence limits constructed about the Bid MTBF to determine compliance to it. Methods by which incentives or penalties may be rewarded or assessed to contractor as a result of the Phase II testing are included. The author next investigated techniques which can be used to determine the maintainability parameters and the accuracy of these parameters. Finally, since the reliability techniques explored were all based on the exponential distribution, techniques were included to prove if the failure rate was exponential. If not, discussions were incorporated on how to handle this situation. (85 pages)

published_or_final_version / Applied Statistics / Master / Master of Social Sciences

No description available.

No description available.

No description available.

No description available.