I have run an analysis outlined below. It would be great if the group could tell me a) if this approach is appropriate and b) if the result is significant (to 95% or 99% level).

Approach

I have 20,000 survey responses to the question 'how likely are you to recommend my event to a friend / colleague', and the repeat behavior of those respondents (i.e. whether they did, or did not, repeat the event the following year).

I have run a Point-biserial correlation between the two variables, and have a value of 11%.

According to Wikipedia, using a transformation will result in a value equivalent to an unpaired t-test. With this high an 'n', an unpaired t-test would be highly significant.

Is this the correct way to interpret this result?

Thanks!