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Category Archives: Research

Linear Regression


The Regression Equation When analyzing data, it is essential to first construct a graph of the data. A scatterplot is a graph of data from two quantitative variables of a population. In a scatterplot, we use horizontal axis for the observations of one variable and a vertical axis for the observations of the other variable. […]



If the information you need is not already available from a previous study, you might acquire it by conducting a census – that is, by obtaining information for the entire population of interest. However, conducting a census may be time consuming, costly, impractical, or even impossible. Two methods other than a census for obtaining information […]

Several Major Distributions of Survival Function


Exponential Distribution The simplest and most important distribution in survival studies is the exponential distribution. In the late 1940s, researchers began to choose the exponential distribution to describe the life pattern of electronic systems. The exponential distribution has since continued to play a role in lifetime studies analogous to that of the normal distribution in […]

Why the Odds Ratio Can Be Used as an Estimate for Relative Risk in a Case-Control Study


The data in a case-control study represent two samples: The cases are drawn from a population of people who have the disease and the controls from a population of people who do not have the disease. The predictor variable (risk factor) is measured, and the results can be summarized in a 2 X 2 table […]