Elements of Statistical Methods Probability (Ch 3) - Statistics
Elements of Statistical Methods Probability (Ch 3) - Statistics
Elements of Statistical Methods Probability (Ch 3) - Statistics
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Combinatorial Counts40 patients in a preliminary drug trial are equally split between men and women.We randomly split these 40 patients so that half get the new drugwhile the other half get a look alike placebo.What is the chance that the “new drug” patients are equally split between genders?“randomly split” means: any group <strong>of</strong> 20 out <strong>of</strong> 40 is equally likely to be selected.P(A) =( 2010) (×20)10) = choose(20,10)ˆ2/choose(40,20)( 4020= dhyper(10,20,20,20) = 0.2476289See documentation in R on using choose and dhyper.( 40) (Enumerating 20 = 137,846,528,820 and 20 210)= 184,7562 cases is impractical.16
Change language