
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 sample set with a capacity of 20 that is divided into groups, the group intervals and their respective frequencies are as follows: (10, 20), 2; (20, 30), 3; (30, 40), 4; (40, 50), 5; (50, 60), 4; (60, 70), 2. Determine the frequency of the sample in the interval $(-∞, 50)$.

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