六年級一班男生人數(shù)是女生的 $\dfrac {7} {6}$
女生人數(shù)是男生人數(shù)的: $1\div \dfrac {7} {6}=\dfrac {6} {7}$
男生人數(shù)是全班人數(shù)的: $\dfrac {7} {6}\div \left ( {1+\dfrac {7} {6}} \right )=\dfrac {7} {6}\div \dfrac {13} {6}=\dfrac {7} {13}$
女生人數(shù)是全班的: $1-\dfrac {7} {13}=\dfrac {6} {13}$
故答案為: $\frac{6}{7}$; $\frac{7}{13}$; $\frac{6}{13}$