When to use getSharedPreferences vs savedInstanceState?

I'm trying to figure out when to use a saved instance state versus loading information from a shared preferences file. I have two variables that I wish to save, time and score. I want to make sure that if the user returns to the game screen that their score and time is saved and restored regardless if it's from onPause state or onStop.

I have three keys:

public static final String ARG_SCORE = "score";
public static final String ARG_TIME = "time";
public static final String SHARED_PREFS = "shared_preferences";

If the game is paused and a dialog is shown, when the user returns should I do

public void onRestoreInstanceState(Bundle savedInstanceState){
int score = savedInstanceState.getInt(ARG_SCORE);
}

or should I do something like:

protected void onResume(){
SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
int score = sharedPref.getInt(getString(R.string.saved_high_score));
}

Overall, I need help understanding the lifecycle and when to store vital information such as time and score of the game. I simply need to avoid the user having to restart in cases they weren't able to finish the game.

Lastly, I'm assumed that the sharedPrefs saves to an xml file. Is this correct? Does anyone have a sample xml for how my sharedPrefs should appear? Do keys which are saved to bundles of savedInstanceState get stored in xml files as well? If so, any examples? If not, where is the information stored?

THANKS!