Tune Up
Six Sigma has many meanings. In its simplest context, Six Sigma can be defined statistically as the attempt to achieve near-perfection by having no more than 3.4 errors per million opportunities, or being 99.997% correct (or defect-free)....
Statistics Roundtable: Player Rankings
The coefficient of variation, sometimes called the relative standard deviation, is often used to assess the quality of an assay, the diversity in organizations or as a benchmark for ranking....
Statistics Roundtable: Predicting Success
Considering that a phase three efficacy clinical trial for a potential new product could cost nearly $100 million, spending time in simulation activities before fully committing to developing a new product has proven to be worthwhile for more companies....
Salary Survey 2008: Seeing Green
Significant salary discrepancies exist among quality professionals depending on where they work, their gender and whether they supervise others, according to an analysis of QP’s 2007 and 2008 salary surveys. Part 1, section 1 leads off the salary survey p...
Statistics Roundtable: The Trusty Jackknife
Outliers are a continual source of problems when analyzing data. A few questionable data points can skew your distribution, make significant results seem insignificant and generally ruin your day....
Online Figures Statistics Roundtable: The Trusty Jackknife
Fixed-effects jackknife estimates eliminating single studies / online Figure 1 Random-effects jackknife estimates eliminating single studies / online Figure 2...
Statistics Roundtable: Match Game
One useful method for evaluating new medical treatments, devices or services involves propensity score methods - matching members of different groups based on a range of characteristics and forming a probability score....
Statistics Roundtable: Likert Scales and Data Analyses
Surveys are consistently used to measure quality. For example, surveys might be used to gauge customer perception of product quality or quality performance in service delivery....
Building a Better Fantasy Baseball Team
Fantasy baseball is a popular game giving sports fans the opportunity to display their baseball expertise in competition with other fans. The game fosters careful planning and research in hopes of outsmarting the rival team. By looking at fantasy...
Statistics Roundtable: Superiority, Equivalence and Non-inferiority
Most statistical tests are performed to show whether two measurements, processes, products or treatments are significantly different from each other and whether we can reject the null hypothesis....
Statistics Roundtable: Different, Equivalent or Both?
In conventional tests of statistical significance, the investigator tries to reject the null hypothesis of no difference between two groups. If the investigator fails, then the hypothesis groups cannot be rejected....
Cumulative Meta-Analysis
Meta-analysis is a set of statistical procedures designed to integrate and synthesize experimental results across independent studies into an overall summary statistic....
