
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
Given a school with a total of 1000 students in the first and second grades, with 400 students in the first grade, and sample means and variances of 165cm and 4, and 170cm and 3, respectively, calculate the population variance.

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