Dice-rolling simulator I know there is a better way to store data.  What is the most concise way to simplify this script?

from random import randint
from sys import exit
import os

os.system('clear')
print "Welcome to the dice rolling simulator!"
raw_input("Press enter to begin.")

total = 0

completed = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

def roll():
    os.system('clear')
    die1 = randint(1, 6)
    die2 = randint(1, 6)
    global total
    total = die1 + die2
    storetotal()
    print "Die 1: %d \nDie 2: %d \nTotal: %d." % (die1, die2, total)
    print "\n\nRoll again?"
    roll_again = raw_input("Press enter to roll again, type 'stats' to view scores, or 'quit' to exit.\n&gt; ")    
    if roll_again == "":
        roll()
    elif roll_again == "stats":
        stats()
    elif roll_again == "quit":
        exit(0)
    else:
        print "I don't know what that means so you get to roll again."
        raw_input("&gt; ")
        roll()

def stats():
    global total
    print "2s: %d \n3s: %d \n4s: %d \n5s: %d \n6s: %d \n7s: %d \n8s: %d" % (completed[0],
                                                    completed[1], completed[2], completed[3], 
                                                    completed[4], completed[5], completed[6])
    print "9s: %d \n10s: %d \n11s: %d \n12s: %d""" % (completed[7], completed[8], 
                                                    completed[9], completed[10]) 
    raw_input("")
    roll()

def storetotal():
    if total == 2:
        completed[0] += 1
    elif total == 3:
        completed[1] += 1
    elif total == 4:
        completed[2] += 1
    elif total == 5:
        completed[3] += 1
    elif total == 6:
        completed[4] += 1
    elif total == 7:
        completed[5] += 1
    elif total == 8:
        completed[6] += 1
    elif total == 9:
        completed[7] += 1
    elif total == 10:
        completed[8] += 1
    elif total == 11:
        completed[9] += 1
    else:
        completed[10] += 1


roll()
Line by line analysis

Use four spaces to indent python code. Never use tabs.

from random import randint
from sys import exit
import os


It is a good practice to do top-level imports (without importing module members). This way it's easier to understand what package the methods come from.

os.system('clear')
print "Welcome to the dice rolling simulator!"
raw_input("Press enter to begin.")

total = 0

completed = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]


Use list comprehensions.

def roll():


Roll method is confusing. You expect it to roll a die, but it processes iterations of the game. A while loop would be more explicit here.

os.system('clear')
die1 = randint(1, 6)
die2 = randint(1, 6)
global total


Global variables are no-no. Never.

total = die1 + die2
storetotal()
print "Die 1: %d \nDie 2: %d \nTotal: %d." % (die1, die2, total)
print "\n\nRoll again?"
roll_again = raw_input("Press enter to roll again, type 'stats' to view scores, or 'quit' to exit.\n&gt; ")    


You're exceeding recommended 80 column length limit.

if roll_again == "":
    roll()


See how I changed this block in a code below.

elif roll_again == "stats":
    stats()
elif roll_again == "quit":
    exit(0)


Return from the method is sufficient here.

else:
    print "I don't know what that means so you get to roll again."
    raw_input("&gt; ")
    roll()

def stats():
global total
print "2s: %d \n3s: %d \n4s: %d \n5s: %d \n6s: %d \n7s: %d \n8s: %d" % (completed[0],                                                                     completed[1], completed[2], completed[3], 
                                            completed[4], completed[5], completed[6])
print "9s: %d \n10s: %d \n11s: %d \n12s: %d""" % (completed[7], completed[8], 
                                                completed[9], completed[10]) 


Indentation here is completely messed up.

raw_input("")
roll()

def storetotal():


PEP8: store_total.

if total == 2:
    completed[0] += 1
elif total == 3:
    completed[1] += 1
elif total == 4:
    completed[2] += 1
elif total == 5:
    completed[3] += 1
elif total == 6:
    completed[4] += 1
elif total == 7:
    completed[5] += 1
elif total == 8:
    completed[6] += 1
elif total == 9:
    completed[7] += 1
elif total == 10:
    completed[8] += 1
elif total == 11:
    completed[9] += 1
else:
    completed[10] += 1


roll()


Improved code

I simplified your roll method to roll2d6 and moved all the other code into main.

import random
import os


def roll2d6():
    die1 = random.randint(1, 6)
    die2 = random.randint(1, 6)
    return die1 + die2


def display_stats(stats):
    for i, result in enumerate(stats):
        print "%ds: %d" % (i + 2, result)


def update_stats(total, stats):
    stats[total - 2] += 1
    return stats


def main():
    stats = [0 for _ in xrange(10)]

    os.system('clear')
    print "Welcome to the dice rolling simulator!"
    raw_input("Press enter to begin.")
    while True:
        os.system('clear')
        total = roll2d6()
        stats = update_stats(total, stats)
        print "Die 1: %d \nDie 2: %d \nTotal: %d." % (die1, die2, total)
        print "\n\nRoll again?"
        roll_again = raw_input((
                "Press enter to roll again, type 'stats' to view scores, "
                "or 'quit' to exit.\n&gt; "))
        if roll_again.lower() == "stats":
            display_stats(stats)
        elif roll_again.lower() == "quit":
            break
        elif roll_again.lower() != "":
            print "I don't know what that means so you get to roll again."

if __name__ == "__main__":
    main()