PPT-Power and Effect Size

Cal State Northridge 320 Andrew Ainsworth PhD 2 Major Points Review What is power What controls power Effect size Power for one sample t Power for relatedsamples t Power for two sample . Jed Friedman, World . Bank. SIEF Regional Impact Evaluation Workshop. Beijing, China. July 2009. Adapted from slides by Esther . Duflo. , J-PAL. Planning Sample Size for . Randomized Evaluations. General question: . Effect Size & Statistical Power. 1. 1. Effect Size. How “meaningful” is the significant difference?. 1. KNR 445. Statistics. Effect sizes. Slide . 3. Significance vs. meaningfulness. As sample size increases, likelihood of significant difference increases. Chapter 8. Hyde, Fennema & Lamon (1990). Mean gender differences in mathematical reasoning were very small.. When extreme tails of the distributions were removed, differences were smaller and reversed direction (favored girls). Laura . Chioda. World Bank. 1. Outline. Ingredients of a general recipe called “Statistical Sampling Theory” . Key message. : a successful design involves some guess work. It is important to have a general rule, but then needs discussion depending on the case at hand. Dr. .. Richy Hetherington. and Dr. . Kim Pearce. Introductions . Today’s Session. Run a live Experiment . Discussion of considerations when setting up experiments. Analyse the results of our experiments with thoughts on what to look out . November 17, . 2015. Allen Kunselman, MA. Division of Biostatistics and Bioinformatics. Department of Public . H. ealth Sciences. Quotes. An approximate answer to the right question is worth a good deal more than an exact answer to the wrong question.. Pam Davis-Kean. Methods Hour. January 20, 2017. I collected my data, I ran my analyses, and nothing is significant. . What . do I do?. Common . Question. Recommendations for Strong and Rigorous Research. r_met. The top 4 SNPs for . r_met. are:. chr9 rs17180299. chr9 rs17083111. chr9 rs62572435. chr5 . rs26411. We want to test SNP by SNP Epistasis for the top 4 SNPs for . r_met. using PLINK.. PLINK Input Files. Office of Methodological & Data Sciences. November . 13, 2015. Sarah Schwartz. www.cehs.usu.edu/research/omds. Quantitative Research. Research Question. Clear, focused & concise question that drives the study. Sample 4. Females. 43% . Work on management positions. 14%. Variable One. 22%. Variable Two. 31%. Variable Three. 34%. Variable Four. 39%. Variable Five. 2 in 5. Additional Descriptive statistics. 80%. Hao. . Zhou & David . Dueber. February 6, 2017. Applied Psychometric Strategies Lab. Applied Quantitative and Psychometric Series. Outline. Fake real life research scenario. Significance testing and statistical errors. PEP507: Research MethodsEffect Size and Statistical Power Prior to conducting the study (apriori), researchers should;estimate the size of a mean difference that is meaningfulidentify a type II error ‘statistically significant’ does not mean ‘important’ . IQ’s of UW undergraduates. Suppose we measured the IQ’s of 10,000 UW undergraduates and found a mean IQ of 100.3. If we were to conduct a one-tailed z-test to determine if this mean is . Power Is. The conditional probability. that one will reject the null hypothesis. given that the null is really false. by a specified amount. and given certain other specifications such as sample size and the criterion of statistical significance (alpha). .