To find the mean quiz score, you add up all the quiz scores and then divide by the number of quizzes.

The scores are: 18, 16, 16, and 12.

1. Sum of the scores:
   $18 + 16 + 16 + 12 = 62$

2. Number of quizzes:
   There are 4 quizzes.

3. Mean quiz score:
   $\text{Mean} = \frac{\text{Sum of the scores}}{\text{Number of quizzes}} = \frac{62}{4} = 15.5$

So, the student's mean quiz score is 15.5.

Would you like further details or have any questions?

Here are five related questions:

1. What is the median quiz score?
2. How would the mean change if the student scored 20 on an additional quiz?
3. What is the range of the quiz scores?
4. How do you calculate the mode of these quiz scores?
5. What is the standard deviation of these quiz scores?

Tip: The mean provides a measure of central tendency, giving you an idea of the average performance across all quizzes.