Is your feature request related to a problem or challenge?

I'm working on the ticket: #10316.

Given that, we'll replace all Precision with Distribution: synnada-ai#63. So, while I make the design for #10316, I presumably use Distribution in statistics.

There is a spot where I'll do the merge for statistics, and it'll be spread to the Distribution.

The specific case is that I need to compute the partition-level statistics, aka, files will be grouped as the filegroup, each file group will be treated as a partition, and different partitions will be processed in parallel. So, the partition-level statistics will be from the merge of the files in a filegroup.

Describe the solution you'd like

Create a function that combines their statistical properties into a new distribution. The most appropriate approach is to create a GenericDistribution that approximates the mixture of the two input distributions.

pub fn merge_distributions(a: &Distribution, b: &Distribution) -> Result<Distribution> {
    ...
}

I'll open a PR and we can do more discussions based on the PR.

Describe alternatives you've considered

No

Additional context

No