Why does the combined segment size of users filling out either form 1 or form 2 equal 12,000?

The size of the combined segment of users filling out either form 1 or form 2 equaling 12,000 is correctly explained by the fact that 3,000 people filled out both forms. This overlap is crucial in understanding how to calculate the total unique users who completed at least one of the forms.

To clarify, the calculation involves using the principle of inclusion-exclusion in set theory. When calculating the total users who filled out either form, one needs to consider:

• The users who filled only form 1 (5,000).

• The users who filled only form 2 (10,000).

• The users who filled both forms (3,000).

If the 3,000 users who completed both forms were counted in both of the other direct counts (5,000 and 10,000), they would artificially inflate the total when simply adding these numbers together. Therefore, the combined segment size is calculated as follows:

Total = (Users filling out only form 1) + (Users filling out only form 2) + (Users filling out both forms)

Total = 5,000 + 10,000 - 3,000

Total = 12,000

This illustrates that counting both forms together