PPT-Having Confidence in our Means:

Confidence Intervals UWEJT9 davelush Scientific Practice Samples are Estimates When we sample a population we end up with a sample mean its our best guess of the real population mean . The square root of the pooled variance is called the pooled standard deviation deviation standard Pooled Example Male and Female Sleep Times Question How much difference is there between how long female and male students slept the previous night Da Robin H. Lock, Burry Professor of Statistics. Patti Frazer Lock, Cummings Professor of Mathematics. St. Lawrence University. Joint Mathematics Meetings. New Orleans, January 2011. Intro Stat at St. Lawrence. Chapter 25 . 1. . devoid. (adj.) . - ___________. . The French fries were so thin, dry, and . devoid. of taste that they seemed like toothpicks.. d. evoid . means. :. . . without. . equal to. C. . Robin H. Lock, Burry Professor of Statistics. St. Lawrence University. Stat Chat. Macalester College, March 2011. The Lock. 5. Team. Robin & Patti. St. Lawrence. Dennis. Iowa State. Eric. UNC- Chapel Hill. Chapter 19 Rocks!. Formulaic Consequences. In our formula, . fractionwise. , z-star is in the top and n is in the bottom.. The terms for these are directly proportional (for z-star) and inversely proportional (for n).. 2015-2016. Overview. L.C. O.L.. Sampling variability. Confidence intervals for population proportion.. Hypothesis testing using confidence intervals. L.C. H.L.. Normal distribution. Sampling variability. When I cover the entire population I get to know the truth – precisely.. That means that when my sample size is high I get a more precise answer.. That means that when my sample size increases my preciseness increases. Chapter 23. Inference About Means . Getting Started. Now that we know how to create confidence intervals and test hypotheses about proportions, . it would . be nice to be able to do the same for means. Confidence Intervals. Scientific Practice. Samples are Estimates. When we . sample. a population, we end up with a sample mean, . . it’s our ‘best guess’ of the real population mean, . µ. the ‘real’ mean of the population is ‘hidden’. Christian Stevens. Technology Enhanced Learning Advisor. University of Wales Trinity Saint David. 1 2 3 . 4 . 5 6 . 7 . 8 9 . 10. Different . sectors, same . Robin Lock. Burry Professor of Statistics. St. Lawrence University. AMATYC Webinar. December 6, 2016. The Lock. 5. Team. Patti & Robin. St. Lawrence. Kari. Harvard. Penn State. Eric. North Carolina. Day 19. A new example, with less information:. Now I want to know about the average height of three year old apple trees. A random sample of 60 trees gave us a standard deviation of 2.8 inches (so we’ll assume . Post Hoc or Multiple Comparison Testing To determine which group means are statistically different Ideally, should test just what groups you want to compare – particularly if small sample size Select type of post hoc testing ( An Overview. Statistical Significance. Only tells you sample results unlikely were the null true.. Null is usually that the effect size is absolutely zero.. If power is high, the size of a significant effect could be trivial..