Use the R package UsingR to download the data file called ai
     Use the R package \"UsingR\" to download the data file (called \"aid\") about monthly payment for federal program to R.  Use R code to check whether it is a vector or matrix. Then assign \"payment\" as a vector based on the payment amounts only by removing the names of the states.  Use the appropriate vector functions to rank, to sort, and to order the payment vector. Call these vectors as rank.payment. sorted.payment, and ordered.payment. Then use R code to make a dataframe (or table) out of these four vectors.  Use R code to save the dataframe or table in the text file called \"table.txt\" in your working directory.  Use R code to find the name of the states with highest and lowest payment. 
  
  Solution
library(UsingR)
data(aid) #read data
#check vector or matrix
 if(is.vector(aid)){
 print(\"Vector\")
 } else if(is.matrix(aid)){
 print(\"Matrix\")
 }
#remove names
 payment <- unname(aid)
#rank, order, sort
 rank.payment <- rank(payment)
 ordered.payment<- payment[order(payment)]
 sorted.payment<-sort(payment)
#create dataframe
 tb <-data.frame(col1 = payment, col2= rank.payment, col3= sorted.payment, col4 = ordered.payment)
#write dataframe
 write.table(tb,\"table.txt\",sep=\"\\t\",row.names=FALSE)
#lowest payment from rank ordering
 attributes(aid)$names[match(1, rank.payment)]
#highest payment from rank ordering
 attributes(aid)$names[match(51, rank.payment)]

