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The Assessment Of Osborne And Waters

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In statistical tests, we must rely on assumptions regarding the variables we used in the analysis. If these assumptions are not met we may arrive at results that are incorrect, or not representative of the population, typically due to a Type I or a Type II error, or an over or under estimation of significance or effect size. Osborne and Waters (n.d., p. 1) quote an 1997 article by Pedhazur stating “Knowledge and understanding of the situations when violations of assumptions lead to serious biases, and when they are of little consequence, are essential to meaningful data analysis” which while a very important point, really only holds importance when researchers test assumptions, an important step in data analysis that is rarely performed. …show more content…

These tests give researchers information about normality, while the K-S tests provide inferential statistics on normality. One of the best tests for outliers is a visual inspection of histograms, as well as frequency distributions or converting data to z-scores. The removal of univariate and bivariate outliers can reduce the probability of Type I and Type II errors, which improve the accuracy of some estimates. It is important to consider that removing outliers is not always desirable, in which case transformations can improve normality. This can complicate the interpretation of the results, and therefore should only be used deliberately and in an informed manner. To accurately estimate the relationship between dependent and independent variables using standard multiple regression, these relationships must be linear in nature. This is why it is so important to examine analyses for non-linear data, as non-linear data will result in a regression analysis that under-estimates the true relationship. Under-estimation carries some risk, in particular an increased chance of Type II errors for the independent variable, and in the case of multiple regression, an increased risk of Type I errors (over-estimation) for other independent variables that share variance with that variable. There are a few primary ways to detect non-linearity in the data. The use of theory or previous research can be used to inform current analyses,

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