spotted amber ladybird, hippodamia variegata (goeze, 1777) (coleoptera: coccinellidae) is an important predator of aphids and some other insect pests. since shape and size variation may affect biological characteristics of an insect, multivariate analysis of shape variations in four geographically isolated populations of h. variegata (isfahan, shahrekord, shiraz, yasuj) was performed based on e...

Background and aims: Nowadays, the age structure of Iran is transitioning from youth to elderly. Although, the elderly population are still accounted for a small portion of the population; however, the population growth rate of this age group is growing compared to the growth of the total population. Therefore, understanding of the changes of this population is necessary. This study aimed to id...

The one-sample paired t-test may be used to test whether the mean difference of two populations is greater than, less than, or not equal to a specific value. Because the t distribution is used to calculate critical values for the test, this test is often called the paired t-test. If the standard deviation of the differences is known, the normal distribution is used instead of the t distribution...

Fiber lengths were analyzed for random samples of medium-density fiberboard (MDF) fibers and wood particles taken from eleven different populations. For six of the samples, the lognormal distribution fit the data, while the Weibull distribution did not. For three of the samples, the Weibull fit the data, while the lognormal did not. For two of the samples, both the lognormal and Weibull fit the...

A nonparametric upper tolerance limit (UTL) bounds a specified percentage of the population distribution with specified confidence. The most common UTL is based on the largest order statistic (the maximum) where the number of samples required for a given confidence and coverage is easily derived for an infinitely large population. However, for other order statistics such as the second largest, ...

Consider s + 1 univariate normal populations with common variance σ2 and means μi, i = 0, 1, . . . , s, constrained by the tree-order restrictions μ0 ≤ μi, i = 1, 2, . . . , s. For certain sequences μ0, μ1, . . . the maximum likelihood-based estimator (MLBE) of μ0 diverges to −∞ as s → ∞ and its bias is unbounded. By contrast, the bias of an alternative estimator of μ0 proposed by Cohen and Sac...

Research in Web caching has yielded analytical tools to model the behavior of large-scale Web caches. Recently, Wolman et al. have proposed an analytical model and used it to evaluate the potential of cooperative Web proxy caching for large populations. This paper shows how to apply the Wolman model to study the behavior of interior cache servers in multi-level caching systems. Focusing on inte...