Is this done "efficiently"?

Can you post the HTML file also please?

The text being stored in the div keeps changing with each call to print, and is over-written by the value in message. That's why the only thing you see is the last thing sent to print.

You can either build the entire output into one call to print, or concatenate the contents of message to the div.

outputDiv.innerHTML += message;

Sure, my pleasure. I couldn't help but take another look at the code, and sticking with the theme of this thread on 'efficiency', I'd recommend building your entire output into one call to print.

var quiz = [
  ['What is the color of grass?', 'green'],
  ['What is 1 + 3?', 4],
  ['Who was the first president of the USA?', 'george washington'],
  ['Who is the current president?', 'barrack obama'],
  ['How many fingers do you have?', 10]
];

var answersCorrect = 0;
var answersCorrectCount = '';
var answersWrong = 0;
var answersWrongCount = '';
var listHTML = '<ol>';
var listHTML2 = '<ol>';
var output = '';

function print(message) {
  var outputDiv = document.getElementById('output');
  outputDiv.innerHTML = message;
}

for (var i = 0; i < quiz.length; i++) {
  var answer = prompt(quiz[i][0]);
  if (answer === quiz[i][1] || parseInt(answer) === quiz[i][1]) {
    answersCorrect++;
    answersCorrectCount = quiz[i][0];
    listHTML += '<li>' + answersCorrectCount + '</li>';
  } else {
    answersWrong++; 
    answersWrongCount = quiz[i][0];
    listHTML2 += '<li>' + answersWrongCount + '</li>';
  }
}

listHTML += '</ol>';
listHTML2 += '</ol>'; // added closing bracket

output += 'You got ' + answersCorrect + ' question(s) right';

output += 'You got these questions correct:';
output += listHTML;

output += 'You got these questions wrong:';
output += listHTML2;

print(output);

I don't have any good advice for you in this regard, because I struggle with this myself. Our score is just a pat-on-the-back for effort, but what really matters is retaining that information - and the best way to do that is to apply it. Apply it to a project, or to helping others on the forum.

For myself, by trying to help others with their code, I actually learn a lot in the process and it helps me to retain the information as I go through some challenge for the n'th time.

I still forget a lot about the fundamentals, but what makes me better than my younger self, is that I'm getting faster at finding the right question to ask, doing a Google search, and understanding the answer I find - or get nudged in the right direction to eventually find the answer. Sometimes the problem I'm trying to solve is just way too over my head and I abandon the problem in favor of spending my time doing something else. For example, I can't yet wrap my head around d3.js. Intermediate and advanced topics of Java give me brain freeze. And I still can't remember how to write a http-server in node.js without reading a tutorial - after a dozen times.

We're all different, but from what I keep reading and hearing is that this is a never ending journey and no matter how many walls we break down, there will be more in our way further ahead - unless, we stop learning and just continue solving the same problem day after day.

Just to add my own two cents here from my own personal experience, I've found that when I watch a video that goes over new things I'm not familiar with, I've found the best way for me to retain that information is to try to make some random, simple programs that use the information I was just taught. I'm a hands on learner, myself, so once I get my hands on something and start using it, I can figure out through trial and error exactly how they work. Then, you can go on to make more complicated programs using the practice you've gained earlier.

I did that method to come up with my paint program: http://marcusparsons.com/projects/sketchmeh. It started off with Andrew Chalkley's awesome course "Simple jQuery Drawing App" and then blossomed into a work I'm proud to show off.

Again, this is just my own personal opinion, and your learning style may be completely different. You just gotta find your groove and be groovy, my friend!