
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
In a class of 50 students, there are 30 boys and 20 girls. Five boys and five girls were randomly asked about their scores in a certain math test. The scores of the five boys were 86, 94, 88, 92, and 90, respectively, and the scores of the five girls were 88, 93, 93, 88, and 93, respectively.  
① This sampling method is a stratified sampling;  
② This sampling method is a systematic sampling;  
③ The variance of the scores of these five boys is greater than the variance of the scores of these five girls;  
④ The average score of the boys in the class is less than the average score of the girls in the class. Among the above statements, the one that is definitely correct is \_\_\_\_\_\_ .

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