Testing mathematical formula

[Seungmin Lee]

* Formula outside code bracket
$$\frac{2}{3}+ \mathbf{\pi}$$ $$\begin{split} W_{idt} = \alpha_{0} &+ \alpha_{1} W_{idt-1} + \alpha_{2} W_{idt-1}^2 + \alpha_{X} X_{it} + \gamma_{t} + \mu_{d} + \mu_{idt} % alpha_{3} PSNP_{it} + \alpha_{4} PSNPamt_{it} \\ \end{split}$$ \end{split} W_{idt} = \alpha_{0} &+ \alpha_{1} W_{idt-1} + \alpha_{2} W_{idt-1}^2 + \alpha_{X} X_{it} + \gamma_{t} + \mu_{d} + \mu_{idt} % alpha_{3} PSNP_{it} + \alpha_{4} PSNPamt_{it} \\ * Formula inside code braket

 \[ \frac{2}{3}+ \mathbf{\pi} \]

 \begin{split}     W_{idt} = \alpha_{0} &+ \alpha_{1} W_{idt-1} + \alpha_{2} W_{idt-1}^2 + \alpha_{X} X_{it} + \gamma_{t} + \mu_{d} + \mu_{idt} %  alpha_{3} PSNP_{it} + \alpha_{4} PSNPamt_{it} \\     \end{split} \end{split}

  W_{idt} = \alpha_{0} &+ \alpha_{1} W_{idt-1} + \alpha_{2} W_{idt-1}^2 + \alpha_{X} X_{it} + \gamma_{t} + \mu_{d} + \mu_{idt} %  alpha_{3} PSNP_{it} + \alpha_{4} PSNPamt_{it} \\

$$\beta + \gamma$$

[Seungmin Lee]

$$W_{idt} = \alpha_{0} &+ \alpha_{1} W_{idt-1} + \alpha_{2} W_{idt-1}^2 + \alpha_{X} X_{it} + \gamma_{t} + \mu_{d} + \mu_{idt} % alpha_{3} PSNP_{it} + \alpha_{4} PSNPamt_{it}$$

[Seungmin Lee]

$$\frac{2}{3}+ \mathbf{\pi}$$

[Seungmin Lee]

$$\hat{x}$$