Free Trial

Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.

Share this Page URL
Help

7.1.2 R Functions t1way, t1wayv2, esmcp,... > Data Management - Pg. 297

Chapter 7 One-Way and Higher Designs for Independent Groups 297 there is now more evidence that the groups differ, but the p-value increases to .17. The reason is that the standard error of the sample mean also increases. Data Management It is common to have data stored in a matrix or data frame where one of the columns contains the outcome variable of interest and another column indicates the level (group identification) of the factor being studied. For example, data dealing with plasma retinol is available from a website maintained by Carnegie Mellon University; it can be downloaded from http://lib.stat.cmu.edu/datasets/Plasma_Retinol. For illustrative purposes, it is assumed that the data have been stored in the R variable plasma as a data frame. The variable names are: 1 2 3 4 5 6 AGE: Age (years) SEX: Sex (1=Male, 2=Female). SMOKSTAT: Smoking status (1=Never, 2=Former, 3=Current Smoker) QUETELET: Quetelet (weight/(height^2)) VITUSE: Vitamin Use (1=Yes, fairly often, 2=Yes, not often, 3=No) CALORIES: Number of calories consumed per day.