Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 20 for “"Sample variance"”.
-
Methods of sample size calculation for clinical trials
Sample size calculations should be an important part of the design of a trial, but are researchers choosing sensible trial sizes? This thesis looks at ways of determining appropriate sample sizes for Normal, binary and ordinal data. The inadequacies of existing sample size and power calculation …
-
Blind regression : understanding collaborative filtering from matrix completion to tensor completion
… the distance between the neighbors. We use the sample variance of the difference in ratings between neighbors as the proximity of the distance. Through error analysis, we show that the minimum sample variance is a good proxy of the prediction error in the estimates. Experiments on real-world …
-
Portfolio risk minimization under departures from normality
… be tuned to capture tail risk. We formulate the sample shortfall minimization problem as a linear program. Using results from empirical process theory, we derive a central limit theorem for the shortfall portfolio estimator. We warn about the statistical pitfalls of portfolio selection based on …
-
Improving Signal Clarity through Interference Suppression and Emergent Signal Detection
… effective for signals that have a near constant sample variance, but is successful at detecting a wide variety of signals, including voice signals. To improve performance, the algorithm uses a feed-forward processing technique. This is helpful for the VAD application because voice does not have a …
-
Monitoring for a Shift in a Process Covariance Matrix Using the Generalized Variance
… the mean vector are affected by a shift in the covariance matrix. As in the univariate case, a chart for monitoring for a change in the covariance matrix should be examined first before examining the chart used to monitor for a change in the mean vector. One such chart is the one that plots the …
-
The construct validity of the behavior assessment system for children
… and Teacher Rating Scales (PRS and TRS). Six samples were considered, including the Normative General and Clinical Samples for each measure (Reynolds & Kamphaus, 1992). Another pair of samples were taken from a database of a Georgia hospital (PRS n = 130, TRS n = 108). The Normative Clinical …
-
Fisher Information Test of Normality
… location among all distributions with the same variance. A new test of normality proposed by Terrell (1995) utilizes the above property by finding that density of maximum likelihood constrained on having the expected Fisher Information under normality based on the sample variance. The test …
-
Selecting expansion factor and number of sampling positions for point and plot sampling
Variance approximations were developed to estimate the variances of total basal area per acre and total volume per acre for both point and plot samples. These variance approximations reflect the role that stand characteristics and expansion factor play in either sampling procedure. Validation of …
-
Some Contributions to Tolerance Intervals and Statistical Process Control
… intervals for exponential random variables and sample variances are constructed under a condition that assumes a known parameter, leading to unbalanced tolerance intervals. Moreover, the existing multivariate distribution-free control charts in the literature lack the ability to identify the …
-
Variance Spectroscopy and its Application to the Study of Single-Wall Carbon Nanotubes
This thesis describes the novel method of variance spectroscopy and its application to characterize single-wall carbon nanotube (SWCNT) dispersions. This technique measures and analyzes changes in photoluminescence intensity caused by statistical variations in the local composition of dilute …
-
Performance of Bootstrap Confidence Region For Binomial Distribution With Unknown Parameters p and m
… moments of all orders, I cannot obtain the mean, variance, and covariance for these estimators. Thus, the Delta Method is used to derive the asymptotic normality of the joint distribution of the Method of Moments estimators. After finding the estimators pˆ, and mˆ , I will work on the Asymptotic …
-
Estimation in Truncated Exponential Family of Distributions
… distribution on 0,T , T > 0 known, whenever the sample mean x (GREATERTHEQ) T/2.</p> <p>(ii) Broeder 1955 shows that the maximum likelihood estimator of the scale parameter of a truncated gamma distribution, with the shape parameter being known, becomes infinite with positive probability whenever …
-
The Nature of Emission-Line Galaxies in Hierarchical Cosmologies
… we use the mock catalogues to study the sample variance of current and forthcoming Ly-alpha surveys. Current surveys should be extended significantly in solid angle to allow a robust measurement of the clustering of Ly-alpha emitters, particularly at z>8. On the other hand, future …
-
U.S. Housing Market Volatility
… volatility. With volatility defined as the sample variance of home value monthly returns during a given quarter, a model of volatility from equilibrium in the housing market is derived. Supply and demand effects on housing return volatility for the U.S. as a whole and for a panel of 16 …
-
Dosage, Severity, Frequency, and Chronicity Effects of Adversity Exposure on Children's Grammar Abilities
… impairment. Previous research has not included samples with sufficient exclusionary criteria, assessments with sufficient diagnostic accuracy, nor comprehensive adversity measurement. Given hypothesized epigenetic mechanisms linking extrinsic factors (e.g., adversity exposure) with intrinsic …
-
The Impact of Peculiar Velocities on Supernova Cosmology
… redshift. Combining the 1σ shift with standard sample variance means that, in general, peculiar velocity correlations can cause a shift in the recovered cosmological parameters of up to 2σ. This suggests that future surveys will have to take these correlations into account to ensure unbiased …
-
Spatio-temporal patterns of soil resources following disturbance in a 40-year-old slash pine (pinus elliottii Engelm.) forest in the Coastal Plain of South Carolina
… treatments, spatial heterogeneity measured by sample variance showed a marked "increase and then decline" temporal pattern in soil moisture, soil available nitrogen and phosphorus. Similar patterns were not found in total soil C and N, and total litter C and N. Harvesting resulted in greater …
-
The Universe through a magnifying glass: Precision cosmology with CMB lensing
… robust inference of cosmological parameters and sample variance cancellation. On the data side, the main section of the thesis focuses on CMB lensing measurements obtained from data release 6 of the Atacama Cosmology Telescope. This work provides a state-of-the-art lensing power spectrum …
-
Identifying predictors of performance of associate degree graduate nurses on the licensing examination
… university in the midwest. The representative sample of the population consisted of 253 associate degree graduate nurses completing the associate degree nursing program and writing the licensing examination during the years 1977 through 1979.One instrument was employed to collect the data. This …
-
Profile Monitoring with Fixed and Random Effects using Nonparametric and Semiparametric Methods
… deal with the collection of profiles as a random sample from a common population. For each case, we formulated two Hotelling's T 2 statistics, one based on the estimated random effects and one based on the fitted values, and obtained the corresponding control limits. In addition,we used two …