
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
Among the following propositions, the correct ones are ____.
① The regression line $\hat y = \hat bx + \hat a$ always passes through the center of the sample points $(\overline x, \overline y)$, and at least one sample point;
② Adding the same constant to each data in a set of data does not change the variance;
③ Using the correlation coefficient $R^{2}$ to characterize the regression effect, the closer $R^{2}$ is to $0$, the better the fitting effect of the model;
④ Using systematic sampling to draw a sample of size $20$ from $160$ students, numbering the students from $1$ to $160, and dividing them into $20$ groups in order of the numbers (groups $1$ to $8$, groups $9$ to $16$, ..., groups $153$ to $160$), if the number drawn from the $16$th group is $126$, then the number determined by drawing lots in the first group is $6$.

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