When a correlation is taken in a sample in which the range of the variables being correlated is limited, it is often desired to apply the correlation to groups with different ranges for the variables. In such situations, a correction for restriction of range (more precisely, restriction of standard deviation) may be necessary. Considered in this…

Aromatic solvents possess the strongest solvency of the hydrogen types, but various air pollution control districts have established maximum limits on the amount that may be present in organic coatings. In the proposed procedure, high efficiency liquid chromatography is used to determine total aromatics in enamels and lacquer thinners, their…

Vapors of trichloroethylene, toluene, methyl ethyl ketone, and butyl cellosolve in air were collected using Scotchpac and Tedlar bags, glass prescription bottles, and charcoal adsorption tubes. Efficiencies of collection are reported. (Author/RH)

The determination of hydrogen sulfide in effluents from coal-fired furnaces and incinerators is complicated by the presence of sulfur oxides (which form acids). Organic compounds also may interfere with or prevent the formation of the cadmium sulfide precipitate or give false positive results because of reaction with iodine. The report presents a…

Distributional characteristics of the measure of sampling adequacy (MSA) were investigated in sample correlation matrices generated from multivariate normal populations with covariance matrix equal to the identity. Systematic variation of sample size and number of variables resulted in minimal fluctuation of the overall MSA from .50. (Author/RC)

Compares the harmonic mean and Kramer unequal group forms of the Tukey test for various: (a) degrees of disparate group sizes, (b) numbers of groups, and (c) nominal significant levels. (RC)

Describes a sampling demonstration, using random numbers generated on a microcomputer, that helps to make the central limit theorem concrete and understandable. (Author/JDH)

Normative sampling procedures were used to determine behavioral compatibility of two disabled students considered academically ready for placement in a regular English class. The procedure compared rate of students' disruptive behavior to range and mean of disruptive behavior of the class considered for placement. (Author/CL)

While violation of the homogeneity of variance assumption has received considerable attention, violation of the assumption of normally distributed data has not received as much attention. As a result, researchers may have the mistaken impression that as long as the assumptions of independence of observations and homogeneity of variance are…