Gerald R. Chase

A Monte Carlo Investigation of the Robustness of T 2

Abstract The robustness of T2 for samples of size 5, 10 and 20 from several bivariate distributions is investigated. Samples are presented from bivariate normal, uniform, exponential, gamma, lognormal and double exponential distributions. Related observations on the one sample t and paired t are also given. Highly skewed distributions resulted in too many extreme values of T2 Other distributions gave conservative results. The use of the t-test and non-simultaneous techniques gave large overall levels of significance.

Total Body Potassium in Normal Children

Extract: Normative data for total body potassium on 462 children (232 boys and 230 girls) are presented. The regression of total body potassium on weight can be described as a straight line for males (grams K = 4.32 + 2.12 × weight) and two significantly different lines for females (grams K = −1.50 + 2.32 × weight for weight ≤ 30 kg, and grams K = 34.90 + 1.11 × weight for weight > 30 kg), with less potassium per kilogram for females weighing more than 30 kg. No sex-related difference is found between 12 and 30 kg. When the regression of total body potassium on height is examined, it is found that a logarithmic transformation of potassium values results in a similar pattern, with no sex-related differences between 100 and 135 cm and less potassium per centimeter in females over this height. For males, log K in grams = 1.761 + 0.0182 × cm of height; and for females, log Kin grams = 1.595 + 0.01942 × cm for height ≤ 135 cm, and log K in grams = 2.574 + 0.01215 × cm for height > 135 cm. The logarithmic transformation of K versus height is proposed as a standard because it reflects changes in slope associated with known physiologic and endocrinologic changes occurring with puberty and may be more sensitive than weight in predicting abnormal values in individual patients.Speculation: Since the regression of total body potassium on height appears to be a straight line common to both sexes 100–130 cm tall, with a diverging line indicating progressively less potassium per centimeter for females over 135 cm in height, these data were compared with available data for infants. The total body K values of infants between 50 and 80 cm in length appear to fall on a line with a steeper slope than values of children 100 to 135 cm tall. This observation suggests that, during the 1st year of life, increasing total body potassium per centimeter of length reflects maturation of body composition. Further extension of such observations to low birth weight infants might be expected to give information on their body composition.

Airborne Pb, Cd, Zn and Cu concentration by particle size near a Pb smelter

Abstract A study of airborne Pb, Cd, Zn and Cu was conducted on 2 farms: a test farm exposed to a lead smelter and associated sources of lead contamination in the New Lead Belt of southeast Missouri, and a control farm outside the lead production area. An Andersen eight-stage impactor sampler was used on both farms to collect air samples during winter, spring and summer seasons. The trace element concentrations were measured by atomic absorption spectrophotometry. The concentrations of all four elements were higher on the test farm than on the control farm in all of the three seasons. Approximately 66% of the Pb. 88% of the Cd. 73% of the Zn and 54% of the Cu was composed of particles smaller than 4.7 μm the upper practical limit of respirable size.

Regulation of Human Lipolysis IN VIVO OBSERVATIONS ON THE ROLE OF ADRENERGIC RECEPTORS

Changes in the plasma free fatty acids of a pancreatectomized subject and in free fatty acids and insulin in 10 normal subjects in response to the in vivo infusion of epinephrine alone, epinephrine plus phentolamine, and epinephrine plus propranolol indicate that both alpha and beta adrenergic receptors are present in human adipose tissue. Under the experimental conditions used, adipose tissue appeared to be more responsive to epinephrine than did the cardiovascular system.

On the Chi-Square Test When the Parameters are Estimated Independently of the Sample

Abstract If the parameters are estimated independently of the sample, the chi-square test statistic for a goodness of fit test has a limiting distribution that is stochastically larger than that of the test of fit for a completely specified distribution. Thus, if the critical values for the test of fit for a completely specified distribution are incorrectly used, the probability that we will reject the null hypothesis when it is true is greater than the desired level of significance.

Body Composition of Negro and White Children

In order to further assess nutritional status of Negro and white children aged 4 and 5 whose hematological and serum protein values were within normal range, body composition studies were done. Total body potassium was measured by whole body counting of gamma emissions of naturally occurring radioactive potassium (40K) with a 2π liquid scintillation counter. Standard anthropometric measurements were also performed. Results show no statistically significant difference in total body potassium in the two groups, regardless of sex. There are fat differences.

A longitudinal study of total body potassium in normal children.

Extract: Most investigators studying changes in body composition during growth agree to the desirability of having longitudinal data. A group of 110 boys and 126 girls, studied annually for 4-5 years with 880 measurements of total body K in a 2π liquid scintillation whole body counter, had total body K vs. height and total body K vs. weight data that fit previously described regression lines.Speculation: Given an adequate diet and environment, children increase their total body K in a predictable amount in reference to skeletal growth.

On Testing for Equality of Two Availabilities

Analytical and Monte Carlo results are used to investigate the robustness of the exact statistical test suggested by Nelson for testing the hypothesis of equality of two availabilities. A non-parametric test based on a generalized U-statistic is proposed which does not depend on the assumption that the times to failure and times to repair are exponentially distributed. Additional Monte Carlo results are used to point out the strengths and weaknesses of this test.