
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
It is known that the values of each individual in a population, in ascending order, are 2, 3, 3, 7, $a$, $b$, 12, 13.3, 18.7, 20. The median of the population is 10.5. The mean of the population is ____.

Present the answer in LaTex format: \boxed{Your answer}
user