
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 an arithmetic sequence ${a_{n}}$, let $S_{n}$ denote the sum of its first $n$ terms. The first term $a_{1}$ is given as $-20$. The common difference is a real number in the interval $(3,5)$. Determine the probability that the minimum value of $S_{n}$ is only $S_{6}$.

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