getdata  = function (x) { assign(x,  read.csv(paste("http://www.calvin.edu/~stob/data/", x, ".csv", 
        sep = "")),pos=1)}
DVB = function (x) {  
   m=read.csv('http://www.calvin.edu/~stob/data/DVB/DVB.csv') ;
   choices=as.vector(m$Files) ;
   choice = menu(choices, graphics=T) ;
   choice = as.character(choices[choice]); 
   varname = strsplit(choice,'\\.')[[1]][[1]];
   assign( varname, read.csv(paste
        ('http://www.calvin.edu/~stob/data/DVB/',choice,sep="")),pos=1)}

get243 = function (x) {  
   m=read.csv('http://www.calvin.edu/~stob/data/index.csv') ;
   choices=as.vector(m$Files) ;
   choice = menu(choices, graphics=T) ;
   choice = as.character(choices[choice]); 
   varname = strsplit(choice,'\\.')[[1]][[1]];
   assign( varname, read.csv(paste
        ('http://www.calvin.edu/~stob/data/',choice,sep="")),pos=1)}     

phats = function (n,r,x,success) {
        replicate(r, 
          sum(   sample(x,n,replace='F') == success ) / n )}