Random Sample Selection
Last week my manager asked me to randomly pick 10%observations from a large data set and then create a listing so that the Data management programmers can QC the data. I want to share some thoughts here … how easy and simple to do random sampling. Approach 1: Data step Approach: In this approach, the observations are shuffled using the RANUNI function which assigns a random number to each observation. Step1 : Generating the Random Vector (shuffling) using the RANUNI function; The RANUNI function generates a random number from a continuous uniform distribution (the interval (0, 1). Step2 : After assigning a random number to each record, the records can then be sorted in ascending or descending order of the random numbers.; data randsamp ; input patno @@; random= RANUNI ( -1 ); * RANUNI function to assign a random number to each record.; * Here the seed is negative integer (-1) so the results are not replicable.; cards; 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 2...