[bash] Shell Scripting: Using a variable to define a path

My problem lies with my confusion with shell variables.

To my understanding, variables allow me to store a value (String in this case) and to call it later in my code. So if I wanted to have a variable that holds the path to some set of scripts, I could ideally just store it like this:

SPTH = '/home/Foo/Documents/Programs/ShellScripts/Butler'

//Later on in the script//
cd $SPTH
./script1

What I'm trying to do, with probably the wrong syntax, is to set the path to variable SPTH.

Then I use cd with argument $SPTH.

Ideally this would allow me to run the file there without typing in the path. However it doesn't work. The $SPTH is ignored and the result is as if cd was used alone.

So what am I doing wrong? And what would be a way to do this?

To add to the above correct answer :- For my case in shell, this code worked (working on sqoop)

ROOT_PATH="path/to/the/folder"
--options-file  $ROOT_PATH/query.txt