noun
significance; statistical significance
Technical term used mainly in statistics and mathematics to indicate that a result is unlikely to have occurred by chance.
このデータの有意性を検定する必要がある。
We need to test the significance of this data.
有意性が認められなかったため、仮説は棄却された。
The hypothesis was rejected because no significance was found.
有意差 specifically means 'significant difference', a common term in hypothesis testing, whereas 有意性 is the broader concept of significance.
Compound of 有意 (yūi, 'significant') + 性 (-sei, '-ness'), a standard Sino-Japanese nominalization pattern.