ou own a stock portfolio invested $20$ percent in Stock Q$,15$ percent in Stock R$,15$ percent in Stock S$,$ and $50$ percent in Stock T$.$ The betas for these four stocks are $1\mathrm{.}77,1\mathrm{.}09,1\mathrm{.}51,$ and $1\mathrm{.}41,$ respectively. What is the portfolio beta?