The length of the new variable created by the tranwrd function is automatically set to 200 bytes if the length is not previously defined. Therefore, the length is 200. Additionally, the value of the variable 'address' after the substitution in the tranwrd function will be '214 London Drive'.
In the provided SAS program, a DO UNTIL loop is used, which will continue executing until the condition (prod > 6) is met. Initially, the variable PROD is implicitly set to 0. The loop increments PROD by 1 in each iteration. The loop will execute as long as PROD is less than or equal to 6. The looping stops when PROD becomes 7 after it is incremented from 6. Hence, the final value of the variable PROD in the output data set is 7.
To complete the merge of the two datasets by the FNAME variable, you need to account for the different names of the key variable in each dataset. In the WORK.EMPLOYEE dataset, the key variable is FNAME, while in the WORK.SALARY dataset, it is NAME. Thus, you should use the RENAME= data set option to standardize the key variable name before performing the merge. The correct syntax for this is 'merge work.employee work.salary (rename = (name = fname));'. This way, the NAME variable in WORK.SALARY is renamed to FNAME, allowing the datasets to be merged by the FNAME variable.