Better quick sample settings

[martinholmer]

Beginning with the new puf.csv file used by Tax-Calculator release 0.9.0, we have found that the old quick-sample settings being used by TaxBrain are no longer very good.

The old settings were to use a random-number seed of 80 and a 0.02 (two percent) sample.
With the old puf.csv file that produced sample results that were within plus/minus one percent of the full sample tax revenues.

But using these old settings with the new puf.csv file produces differences of more than plus/minus one percent in every year with the largest difference being over 2.8 percent.

We have found that changing the settings to a random-number seed of 180 and a sampling fraction of 0.05 (five percent) restores the old situation in which the sample results are within plus/minus one percent of the full sample tax revenues. For more details, see Tax-Calculator pull request 1441.

It seems as if TaxBrain users who use this feature (if there are any) are going to notice this change. So, it would seem like a simple enhancement to change the settings to 180 and 0.05.

@MattHJensen @feenberg @GoFroggyRun @PeterDSteinberg @brittainhard

Unless others object to this enhancement, perhaps @GoFroggyRun could prepare a webapp-public pull request that implements the new settings and changes the label on the button so that it says 5% instead of %2.

[martinholmer]

Issue #574 will be resolved when PolicyBrain uses packages taxcalc>=0.12.0, which include the changes in Tax-Calculator pull request 1577.