Monty Hall simulator in Python 3.x
Readability:

you should have 2 newlines after each function definition
you should use augumented assignments where possible
you should define each method in a logical order (e.g: if you're calling a function inside another function, the later should be defined first). That's rather a personal preference because you can't do this everytime.
you should have a space around operators and delimiters
you should make your print() statements more compact
variable names should be snake_cased. The same goes for method names.
at the beginning of each function you should define a docstring

Now, let's dig into each function:

in def statistics() you should use format() and join those two prints into a single one:


def statistics(wins, times_to_run):
    &quot;&quot;&quot;Print the statistics&quot;&quot;&quot;
    print(&quot;The computer won {} times&quot;
          &quot;This means the computer won {} % of the time&quot;.format(wins, (wins / times_to_run) * 100))


as mentioned above:


def setup_doors(always_change_choice):
    &quot;&quot;&quot;Set up the winning door&quot;&quot;&quot;
    winning_door = random.randint(1, 3)
    computer_guess = random.randint(1, 3)

    print(&quot;The winning door is {}.\n&quot;
          &quot;The computer guessed door number {}&quot;.format(winning_door, computer_guess))

    return play_game(winning_door, computer_guess, always_change_choice)


in def run(change_choice, times_to_run) you should avoid that multiple condition by using the lower function. You can also use the enumerate() to get rid off that variable definition, and replace i by _ as you don't use it:


def run(change_choice, times_to_run):
    &quot;&quot;&quot;Some description here&quot;&quot;&quot;
    for wins, _ in enumerate(range(times_to_run)):
        if change_choice.lower() == 'y':
            wins += setup_doors(True)
        else:
            wins += setup_doors(False)

    # Display amount of times won/percentage of games won
    statistics(wins, times_to_run)


in def setup() I'd just join the print statements:


def setup():
    &quot;&quot;&quot;Basic greeting/explaining what to do.&quot;&quot;&quot;
    print(&quot;\n\n&quot;
          &quot;There are 3 doors. One is a winner. The computer \n&quot;
          &quot;will try guess the right one. After the first \n&quot;
          &quot;guess, one door is shown to be a loser. The computer \n&quot;
          &quot;can then change it's choice to the remaining door.\n&quot;)

    # Display choices and get input
    change_choice = input(&quot;Should the computer always change it's choice? y/n\n:&gt; &quot;)
    runs = int(input(&quot;How many times should this run?\n:&gt; &quot;))
    run(change_choice, runs)

// To be continued. I have to leave the office.