[R] Chi-Square test and survey results

An organization has asked me to comment on the validity of their recent all-employee survey. Survey responses, by geographic region, compared with the total number of employees in each region, were as follows: ByRegion All.Employees Survey.Respondents Region_1735

[R] Quadratic regression: estimating the maximizing value

A bioligist colleague sent me the following data. x Y 3 1 7 5 148 240 (Yes, only four data points.) I don't know much about the application, but apparently there are good empirical reasons to use a quadratic model. The goal is to find the X value which maximizes the respons

[R] prop.test() - need algorithm or reference

Preparing a paper for a medical journal. Using the prop.test() function in R (v2.4.0) to compare two groups' response to data like the following. A sample of 100 individuals from Population I, 18 with positive readings from a certain test, vs. A sample of 148 individuals from Population