MATLAB: What does this code represents? and why rand() has no value between parentheses

Question

function [outcome]=customer
x=rand() ;
if x <= 0.2
    outcome = 1 ;
else
    outcome = 0;
end

Answer 1

It defines a function which returns either 1 or 0, where 1 has ~=20% probability. Simpler code:

customer = @()+(rand(1)<=0.2);

"why rand() has no value between parentheses?"

Did you read the rand documentation? It explains the different rand syntaxes.