Given that Stock $Y$ has a beta of $1\mathrm{.}05$ and an expected return of $13$ percent, and Stock $Z$ has a beta of $0\mathrm{.}70$ with an expected return of $9$ percent, along with a risk$-$free rate of $4\mathrm{.}5$ percent and a market risk premium of $7\mathrm{.}2$ percent, evaluate the valuation of Stock $Y$ and $Z.$

Are they correctly priced, undervalued, or overvalued in the context of the Security Market Line $($SML$)?$

$($Note: Support your assessment by calculating and comparing the reward$-$to$-$risk ratios of the stocks with the market's ratio and by analyzing their respective positions in relation to the SML$.)$