User:Laxori666

Random maths:

$\sum _{i=1}^n{a}_i{\mu }_i$

$\sum _{i=1}^n\sum _{j=1}^m{a}_i{b}_j\mathrm{Cov}(Y_i,X_j)$

$n\left(\frac{r}{N}\right)\left(\frac{N-r}{N}\right)\left(\frac{N-n}{N-1}\right)$

$\mathrm{E}(g(Y_1)|Y_2=y_2)=\underset{-\mathrm{\infty }}{\overset{\mathrm{\infty }}{\int }}g(y_1)f(y_1|y_2)d{y}_1$

$\underset{-\mathrm{\infty }}{\overset{\mathrm{\infty }}{\int }}x\frac{n!}{(n-1)!}(1-F(x){)}^{n-1}f(x)dx=\underset{-\mathrm{\infty }}{\overset{\mathrm{\infty }}{\int }}xf(x)dx$

$\frac{(n-1)S^2}{{\sigma }^2}$ $S^2$ ${\mathrm{X}}^2$ $\mu$ ${\sigma }^2$

$\sqrt{n}\left(\frac{\overline{Y}-\mu }{S}\right)$

$\frac{(\overline{X}-\overline{Y})-({\mu }_1-{\mu }_2)}{\sqrt{\frac{{\sigma }_1^2}{n_1}+\frac{{\sigma }_2^2}{n_2}}}$

$\frac{(\overline{X}-\overline{Y})-({\mu }_1-{\mu }_2)}{\sqrt{\frac{S_p^2}{n_1}+\frac{S_p^2}{n_2}}}$

$\overline{Y}$

$N(\mu ,{\sigma }^2)$

$N({\mu }_1,{\sigma }_1^2)$ $N({\mu }_2,{\sigma }_2^2)$