In what ways can improper variable assignment, such as missing dollar signs in variable names, affect the execution and output of PHP code?

Improper variable assignment, such as missing dollar signs in variable names, can lead to PHP code errors as the interpreter won't recognize the variable correctly. This can result in unexpected behavior, errors, or incorrect output in the code. To fix this issue, always ensure that variable names start with a dollar sign ($) in PHP.

// Incorrect variable assignment
name = "John";
echo $name;

// Correct variable assignment
$name = "John";
echo $name;