correlation

noun

a statistical relation between two or more variables such that systematic changes in the value of one variable are accompanied by systematic changes in the other
1つの変数の規則正しい変化に伴って、別の変数が規則正しく変化するような、2つ以上の変数の統計的な関連
a statistic representing how closely two variables co-vary
2つの変数がどの程度密接に共変するかを表した統計

it can vary from -1 (perfect negative correlation) through 0 (no correlation) to +1 (perfect positive correlation)
−1（完全な負の相関）から0（相関なし）、＋1（完全な正の相関）まで取りうる
- what is the correlation between those two variables?
  それらの2つの変数の相関関係は何ですか？
a reciprocal relation between two or more things
2つ以上の物事における相互関係