Jerrold H. Zar

Northern Illinois University · Department of Biological Sciences

In a study of the relationship between two variables, the use of measures of correlation assumes that neither is functionally dependent upon the other. So, for example, we might ask whether body weight is related to height in 35-year-old men; or whether examination scores in music theory are related to examination scores in mathematics for first-ye...

The classical Whitworth and Jablonski models of circular runs are reviewed, and the Jablonski model is found to be inappropriate in biological research. Expectations of the mean and variance of circular runs identical to those derived from the Whitworth model are obtained from a third model in which the circle is viewed internally with a focus on t...

A BASIC microcomputer program is presented, which calculates several indices of reliability of a screening test: sensitivity, specificity, positive predictive value, and negative predictive value.

The Poisson distribution may be employed to test whether mutation frequencies differ from control frequencies. This paper describes how this testing procedure may be used for either one-tailed or two-tailed hypotheses. It is also shown how the power of the statistical test can be calculated, the power being the probability of correctly concluding t...

1.1. Male and female little brown bats were collected on 7 dates during hibernation and on one date prior to hibernation.2.2. The predominant fatty acids in brown fat were 16:0 and 18:1, with lesser proportions of 16:1, 18:0 and 18:2, and small amounts of others; 16:0 decreased, while 18:1 increased, during hibernation.3.3. The major fatty acids in...

A complete count of exuviae from a yard of @?0.1 ha revealed 158,054 emerging periodical cicadas (Magicicada cassini) of which 31% died from faulty eclosion. Mutual interference and/or delay owing to a shortage of vertical perching places appears to be responsible, rather than poor nutrition. We argue that cicadas feeding underground are protected...

Warm- (17 degrees C) and cold-acclimated (8 degrees C) young-of-the-year, 1-year-old, and 2-year-old common shiners, Notropis cornutus (Mitchell) were exposed for 24 hr to sublethal doses (1.0, 0.25, and 0.05 microgram/L) of malathion to determine the effect of environmental concentrations of this compound on temperature selection. All three factor...

Sixteen formulae for approximating percentage points of χ2 were examined at each of 15 significance levels. The formula of Wilson and Hilferty is fairly good at most significance levels, but the best approximations without resorting to computer capability are obtained using the Cornish-Fisher expansion or an empirically derived improvement of the S...

Preferred temperatures were determined in a laboratory temperature gradient for the common shiner Notropis cornutus (Mitchill). Preferred temperature was correlated with age, size, season, and nutritional state. Preferred temperatures were higher than, and positively related to acclimation temperatures in all groups. Age, size, and starvation did n...

1.1. The fatty acid compositions of the adipose tissue, brain, and foot skin were determined for an Emperor Penguin.2.2. In the adipose tissue, fatty acids 20:1, 20:4, 14:0, 16:0, and 18:1 were the major components, primarily 20:1 and 20:4. Part of this is correlated with the animal's food, and comparisons with the Adélie Penguin are made.3.3. The...

Kolmogorov-Srnirnov one-sample test isappropriate fortesting goodness of fit of a hypothesized population distributionto a sampled population distribution (Bradley, 1968; Siegel,1956; lar, 1974).If F(X) is the hypothesized cumulative frequency of thevariable X [i.e., F(X) is the number of cases expected to be lessthan or equal to XJ, and S(X) is th...

A table of critical values of the Spearman rank correlation coefficient, r8, is given for n = 4(1)50(2) 100, for nine levels of significance: α = 0.50, 0.20, 0.10, 0.05, 0.02, 0.01, 0.005, 0.002, 0.001.

Incluye índice

1.1. The least--squares fitting of the allometric model, M = aWb, to avian standard metabolism (M)-body weight (W) relationships is shown to yield different results from those obtained from the fitting of its logarithmic transformation, log M = log a + b log W.2.2. The allometric model is fitted to data from eight avian orders, and b values for the...

The allometric equation Y = βXα is widely used as a regression model in biology. The common procedure for fitting this model by the method of least squares involves the logarithmic transformation of both variables: log Y = log β + α log X. This transformation procedure results in a least squares solution which only approximates β and α and often th...

When a simple linear regression equation has been derived using observations recorded on either the Fahrenheit or Celsius temperature scale, one can determine what equation would have resulted had the observations been made using the other temperature scale. Conversions are described for such transformations. See full-text article at JSTOR

1.1. A natural population of ladybird beetles, Coleomegilla maculata, was sampled at eight intervals during hibernation.2.2. Oleic acid (18:1) accounted for more than 60 per cent of the total fatty acids of the beetles.3.3. The fatty acid composition of the beetles remained fairly constant throughout hibernation, except for a great increase in the...

The role of lipids in the physiology of hibernating mosquitoes has long been recognized. Harwood and Takata (1965) demonstrated that temperature and photoperiod stimulate lipid deposition prior to hibernation. As early as 1935, Buxton pointed out that 85% of the fat reserves of hibernating Culex pipiens is exhausted during hibernation. More recentl...

Equations are presented (1) to determine the specific gravity of a glycerol-water solution necessary to maintain a desired relative humidity in a small experimental chamber and (2) to predict the relative humidity which would be maintained by a given glycerol-water solution. The woodlouse, Tracheoniscus rathkei Brandt can survive its normal life sp...

Computing formulae are given, along with an example, to show that the Shannon and Brillouin indices of diversity can be calculated with equal ease. A table is presented for rapid calculation of both indices, as well as Basharin's standard error.