PPT-Slide 1 Comparing Several Means: ANOVA

Understand the basic principles of ANOVA Why it is done What it tells us Theory of oneway independent ANOVA Following up an ANOVA Planned contrastscomparisons Choosing contrasts Coding contrasts. NR 245. Austin Troy. Based primarily on material accessed from Garson, G. David 2010. . Univariate GLM, ANOVA, and ANCOVA. . Statnotes. : Topics in Multivariate Analysis.. http://faculty.chass.ncsu.edu/garson/PA765/statnote.htm. Analysis of Variation. Math 243 Lecture. R. Pruim. The basic ANOVA situation. Two variables: 1 Categorical, 1 Quantitative. Main Question: Do the (means of) the quantitative variables depend on which group (given by categorical variable) the individual is in?. Unweighted. MEANS ANOVA. Data Set “. Int. ”. Notice that there is an interaction here.. Effect of gender at School 1 is 155-110 = 45.. Effect of gender at School 2 is 135-120 = 15.. Weighted means. Lecture #. 28. . Thursday. , . December 1, . 2016. Textbook: . 16.1. • Generalize the two-sample t-test to more than two samples.. • Explain how testing equality of means can be rephrased as a test of variance (“Analysis of variance”).. (a.k.a. Analysis of Variance). 1. Outline:. Testing for a difference. in means. Notation. Sums of squares. Mean. squares. The. F distribution. The. ANOVA table. Part II: multiple. comparisons. Worked example. 28. . Thursday. , . December 1, . 2016. Textbook: . 16.1. • Generalize the two-sample t-test to more than two samples.. • Explain how testing equality of means can be rephrased as a test of variance (“Analysis of variance”).. 13. Section. Comparing Three or More Means (One-Way Analysis of Variance). 13.1. Objectives. Verify the requirements to perform a one-way ANOVA. Test a hypothesis regarding three or more means using one-way ANOVA. At its lowest level it is essentially an extension of the logic of . t. -tests to those situations where we wish to . compare the means of three or more samples concurrently.. ANOVA. One-way ANOVA. One IV and one DV. 19. Introduction. (slide 1 of 3). The procedure for analyzing the difference between more than two population means is commonly called . analysis of variance. , or . ANOVA. .. There are two typical situations where ANOVA is used:. The . Multivariate. Approach. One-Way. Cross-Species-Fostering. House mice onto house mice, prairie deer mice, or domestic Norway rats.. After weaning, tested in apparatus with access to tunnels scented like clean pine shavings, house mouse, deer mouse, or rat.. LM ANOVA 2. 2. Example -- Background. Bacteria -- effect . of temperature (10. o. C & 15. o. C) and relative humidity (20%, 40%, 60%, 80%) on growth rate (cells/d. ).. 120 . petri . dishes with a growth . ANOVA is comparison of means. Each possible value of a factor or combination of factor is a treatment.. The ANOVA is a powerful and common statistical procedure in the social sciences. It can handle a variety of situations.. Chapter 9. Review of Simulation-Based Tests. One proportion: . We created a null distribution by flipping a coin, rolling a die, or some computer simulation. . We then found where our sample proportion was in this null distribution.. ANOVA makes assumptions about error for significance tests. What are the assumptions?. What might happen (why would it be a problem) if the assumption of {normality, equality of error, independence of error} turned out to be false?.