User:Laxori666

Random maths:

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

$\sum _{i=1}^{n}\sum _{j=1}^{m}a_{i}b_{j}\operatorname {Cov} (Y_{i},X_{j})$

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

$\operatorname {E} (g(Y_{1})|Y_{2}=y_{2})=\int _{-\infty }^{\infty }g(y_{1})f(y_{1}|y_{2})dy_{1}$

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

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

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

${\frac {\left({\bar {X}}-{\bar {Y}}\right)-\left(\mu _{1}-\mu _{2}\right)}{\sqrt {{\frac {\sigma _{1}^{2}}{n_{1}}} {\frac {\sigma _{2}^{2}}{n_{2}}}}}}$

${\frac {\left({\bar {X}}-{\bar {Y}}\right)-\left(\mu _{1}-\mu _{2}\right)}{\sqrt {{\frac {S_{p}^{2}}{n_{1}}} {\frac {S_{p}^{2}}{n_{2}}}}}}$

${\bar {Y}}$

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

$N(\mu _{1},\sigma _{1}^{2})$ $N(\mu _{2},\sigma _{2}^{2})$