نتایج جستجو برای: sample t

تعداد نتایج: 1077554  

Journal: :The British journal of mathematical and statistical psychology 2007
Wei-Ming Luh Jiin-Huarng Guo

Yuen's two-sample trimmed mean test statistic is one of the most robust methods to apply when variances are heterogeneous. The present study develops formulas for the sample size required for the test. The formulas are applicable for the cases of unequal variances, non-normality and unequal sample sizes. Given the specified alpha and the power (1-beta), the minimum sample size needed by the pro...

Journal: :Studies in health technology and informatics 2013
Ariana E. Anderson Mark S. Cohen

Although the placebo effect is known to have a strong impact on the outcomes of clinical trials, methods for measuring it are limited to physiological observations. We propose a method of localizing, identifying and measuring placebo and treatment-induced networks in the brain using functional neuroimaging. Measuring the relative activation of these "placebo" brain networks serves as a proxy fo...

2015
Denis Cousineau

Power is defined as the probability of correctly detecting an effect. It is often noted , where the converse, ̄ is the probability of a type-II error (not rejecting H0 when there is an effect). When planning a new experiment, it is generally recommended to have a power of at least .80. Suppose that your design has very little power and suppose further that you found a significant effect. Since y...

2015
ZAHRA JOUHARI AFSHAR PIRASTEH GHOLAM REZA GHASSEMI LEILA BAZRAFKAN

INTRODUCTION The people's mental, intellectual and physical non-readiness to confront earthquake may result in disastrous outcomes. This research aimed to study of effects of a training intervention on health connector's knowledge regarding their approach to earthquake in health-training centers in East of Tehran. METHODS This research which is a semi-experimental study was designed and execu...

Journal: :Transfusion 2017
Aaron S Hess John R Hess

The R function t.test() can be used to perform both one and two sample t-tests on vectors of data. The function contains a variety of options and can be called as follows: > t.test(x, y = NULL, alternative = c("two.sided", "less", "greater"), mu = 0, paired = FALSE, var.equal = FALSE, conf.level = 0.95) Here x is a numeric vector of data values and y is an optional numeric vector of data values...

2007
Zahir Raza Fady Alajaji

Channel optimized ve tor quantization (COVQ), as a joint sour ehannel oding s heme, has proven to perform well in ompressing a sour e and making the resulting quantizer robust to hannel noise. Unfortunately like its ounterpart in the noiseless hannel ase, the ve tor quantizer (VQ), the COVQ en oding omplexity is inherently high. Sample adaptive produ t quantization was re ently introdu ed by Ki...

2007
Hongyuan Cao

Abstract. Let X1, ..., Xn1 be a random sample from a population with mean μ1 and variance σ 2 1 , and Y1, ..., Yn2 be a random sample from another population with mean μ2 and variance σ 2 2 independent of {Xi, 1 ≤ i ≤ n1}. Consider the two sample t-statistic T = X̄−Ȳ −(μ1−μ2) √ s1/n1+s 2 2/n2 . This paper shows that lnP (T ≥ x) ∼ −x2/2 for any x := x(n1, n2) satisfying x → ∞, x = o(n1 + n2) as n...

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