In order to find the percent error, we need to first find the difference between what was expected and what is actually costed. We do this by subtracting:

So now we know that the expected amount was off by $63. To find the percent error, we need to take this $63, and divide it by the amount that was estimated. Let's do that now:

However this is in decimal form. We need to multiply by 100 in order to get it in a percent:

Now we know that
the percent error of the hospital bill estimate is 13.64%.