McKay’s chi-square approximation for the coefficient of variation is type II noncentral beta distributed and asymptotically normal with mean n 1 and variance smaller than 2ðn 1Þ. r 2007 Elsevier B.V. All rights reserved.

In the common nonparametric regression model Yi = m(Xi) + σ(Xi) i we consider the problem of testing the hypothesis that the coefficient of the scale and location function is constant. The test is based on a comparison of the observations Yi/σ̂(Xi) with their mean by a smoothed empirical process, where σ̂ denotes the local linear estimate of the scale function. We show weak convergence of a cente...

In this paper we proposed two new confidence intervals for the normal population mean with known coefficient of variation. This situation occurs normally in environment and agriculture experiments where the scientist knows the coefficient of variation of their experiments. We propose two new confidence intervals for this problem based on the recent work of Searls [5] and the new method proposed...

We consider the problem of selecting the normal population with the smallest coefficient of variation, which is a natural goal when the means as well as the variances of the populations are unknown and unequal. The indifference-zone approach (Bechhofer 1954) to this problem has been previously considered by Choi, Jeon and Kim (1982). We review their selection procedure and provide tables of sam...

To understand how a single neurone processes information, it is critical to examine the relationship between input and output. Marsalek, Koch and Maunsell’s study focused on output jitter (standard deviation of output interpike interval) found that for the integrate-and-fire (I&F) model this response measure converges towards zero as the number of inputs increases indefinitely when interarrival...

Inference for the mean of a normal distribution with known coefficient of variation is of special theoretical interest because the model belongs to the curved exponential family with a scalar parameter of interest and a two-dimensional minimal sufficient statistic. Therefore, standard inferential methods cannot be directly applied to this problem. It is also of practical interest because this p...

Coefficient of variation has been widely used as a measure of precision of measurement equipment in particular for medical laboratories. The objective of this paper is to Inference for the coefficient of variation in uniform distributions. By using the two approaches of central limit theorem and generalized variable, confidence interval for coefficient of variation are considered. The coverage ...

The percentage of vocalic intervals (%V) and the standard deviation of consonantal intervals (deltaC) in a speech signal are two dimensions according to which languages of different rhythm classes (e.g. stress-timed, syllable-timed) seem to be differentiable on an acoustic level (Ramus et al., 1999). In this context it has been found that especially deltaC varies considerably as a function of s...

Demographic heterogeneity is a central theoretical construct in organizational demography research. The most commonly used measure of demographic heterogeneity is the coefficient of variation. I critically evaluate the rationale for using this measure and show that the use of the coefficient of variation raises a number of methodological and interpretive problems. Empirical analyses of turnover...