
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 set of sample data $(x_1, y_1), (x_2, y_2), \ldots, (x_n, y_n)$ ($n \geq 2$, $x_1, x_2, \ldots, x_n$ are not all equal) plotted on a scatter plot, if all the points $(x_i, y_i)$ ($i=1, 2, 3, \ldots, n$) lie on the line $2x+y-1=0$, then the sample correlation coefficient $r$ of this set of sample data is $\boxed{\text{\_\_\_\_\_\_}}$.

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