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Category Archives: Medical Statistics

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. […]

Inferences for Population Standard Deviations


Inferences for One Population Standard Deviation Suppose that we want to obtain information about a population standard deviation. If the population is small, we can often determine 𝜎 exactly by first taking a census and then computing 𝜎 from the population data. However, if the population is large, which is usually the case, a census is […]



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 […]

Inferences for Population Proportions


Confidence Intervals for One Population Proportion Statisticicans often need to determine the proportion (percentage) of a population that has a specific attribute. Some examples are: the percentage of U.S. adults who have health insurance the percentage of cars in the United States that are imports the percentage of U.S. adults who favor stricter clean air […]

Nonparametric Methods of Estimating Survival Functions


Of the three survival functions, survivorship or its graphical presentation, the survival curve, is the most widely used. Examples include product-limit (PL) method of estimating the survivorship function by Kaplan and Meier, life-table analysis, relative survival rate, five-year surival rate, and corrected survival rate. Product-limit method is applicable to small, moderate, and large samples. However, […]