Error in Blog Post Code

Found this confidence interval post very helpful, but the code didn't' work properly for me until I changed the 'rates' table name to 'conversion' in the outermost SELECT statement:

select
  rates.n as users,
  rates.x as conversions, 
  intervals.n as users,
  intervals.x as conversions,
  p - se * 1.96 as low,
  intervals.p as mid,
  p + se * 1.96 as high
from (
  select
    rates.*,
    sqrt(p * (1 - p) / n) as se -- calculate se
  from (
    select
      conversions.*,
      (x + 1.92) / (n + 3.84)::float as p -- calculate p
    from (
      -- Our conversion rate table from above
      select
        count(1) as n,
        sum(case when converted then 1 else 0 end) as x
      from users
      group by date_trunc('month', created_at);
    ) conversions
  ) rates
) intervals

Anyone else experience this issue?

https://www.periscopedata.com/blog/how-to-calculate-confidence-intervals-in-sql

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