If not, you must select the threat to internal validity from one of the nine sources introduced in Part 1. Great for students. A great site for those needing to calculate sample size or power for research. Easy to use. A fair amount of the links on this page do not work, and the page appears to be abandoned.
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Poorly organized, and difficult to find helpful information. No International Research International Research Provides confidential, professional, action research and consultation for clients' psychological and social problems. Action research includes a study of your organization's particular questions, a thorough review of information available in the field, and implementation of the solutions developed which fit your unique needs. This page is their homepage which serves as a contact point. This site provides a link to the Bayesian Calculator, which calculates test sensitivity, specificity, predictive values, and likelihood ratios.