Significant digits in a float?

[Chris Angelico]

On Wed, Apr 30, 2014 at 10:13 AM, Ben Finney <ben at benfinney.id.au> wrote:
> The problem is you won't know *which* 90% is accurate, and which 10% is
> inaccurate. This is very different from the glass, where it's evident
> which part is good.
>
> So, I can't see that you have any choice but to say that *any* of the
> precision predictions should expect, on average, to be (10 + 1 + …)
> percent inaccurate. And you can't know which ones. Is that an acceptable
> error rate?

But they're all going to be *at least* as accurate as the algorithm
says. A figure of 31.4 will be treated as 1 decimal, even though it
might really have been accurate to 4; but a figure of 27.1828 won't be
incorrectly reported as having only 2 decimals.

ChrisA