Question { Quintiles, 4026 }

What's the difference between VAR A1 - A4 and VAR A1 - A4?

Answer

I guess you mean: difference between Var A1-A4 & Var A1--A4!
A1-A4: assumes the variable names as A1,A2,A3,A4 sequentially.
whereas,
A1--A4 : writes all the variables of the data set which are between the variables: A1 & A4,
eg: it can be name,Id etc.

Question { Quintiles, 1618 }

What are _numeric_ and _character_ and what do they do?

Answer

_numeric_ & _character_ are mostly used in:
1. Defining arrays: if an array is defined as _numeric_ that means it expects all values stored in it to be numeric ONLY! And if we define array as _character_ it expects only character values to be stored within it

2. With proc print, if we use these, it prints only numeric or only character variables of the data set!

Question { Quintiles, 1453 }

How would you create multiple observations from a single observation?

Answer

using Proc transpose