
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 certain region, there are 21 primary schools, 14 middle schools, and 7 universities. A stratified sampling method is used to select 6 schools from these for a vision survey among students.  
(1) Determine the number of primary schools, middle schools, and universities that should be selected respectively;  
(2) If 2 schools are randomly selected from the 6 schools for further data analysis, calculate the probability that both selected schools are primary schools.

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