Changes for version 0.06
- lack of a variance value does not throw a croak but returns zero.
- removed ztest method - send stdev divided by sqrt(N) to zscore instead;
- series_test() returns same values and accepts same args as basic test,
- $z_value = $zed->p2z($p) - don't have to use named args here, as already in 'z2p'
- can send just a single value to series_update(), unkeyed, too
- no argument "error" recognized - use "variance" or "stdev"
Modules
Basic deviation ratio: observed less expected (with optional continuity correction) divided by root variance