In Multiple linear regression models, problems arise when serious multicollinearity or influential outliers are present in the data. Failure to include significant quadratic or cross-product terms result in model specification error. Simple scatter plots are most of the time not effective in revealing the complex relationships of predictor variables or data problems in multiple linear regressio...

In mixture experiments, estimation of the parameters is generally based on ordinary least squares (OLS). However, in the presence of multicollinearity and outliers, OLS can result in very poor estimates. In this case, effects due to the combined outlier-multicollinearity problem can be reduced to certain extent by using alternative approaches. One of these approaches is to use biased-robust reg...

Econometrics textbooks generally conclude that in regression, because the calculation of path estimate variances includes a variance inflation factor (VIF) that reflects correlations between “independent” constructs, multicollinearity should not cause false positives except in extreme cases. However, textbook treatments of multicollinearity assume perfect measurement – rare in behavioral resear...

China is a country that is arousing a large amount of interest as a new mega-market, as it opens itself to a market-orientated economy and expands at a remarkable rate. However, the influx of international investment, new business opportunities and advertising from overseas has seen Chinese consumers being exposed to potentially offensive advertising products and images. While some products and...

Fuzzy clusterwise regression has been a useful method for investigating cluster-level heterogeneity of observations based on linear regression. This method integrates fuzzy clustering and ordinary least-squares regression, thereby enabling to estimate regression coefficients for each cluster and fuzzy cluster memberships of observations simultaneously. In practice, however, fuzzy clusterwise re...

The article is the investigation of heavy metals pollution on surface waterin Ikoli River and Epie creek in Yenagoa, metropolis, Bayelsa State. Pb,Cd, Ni, Cr, Fe, Zn was determined evaluated using GeographicalInformation System. Zinc concentration below permissible limitof 3 mg/L all locations sampled. Iron 77.78% limit ofWHO 2011 0.3 while other examined Riverand are highly polluted. index for...