$1.$ You own a stock portfolio invested $15$ percent in Stock Q$,35$ percent in Stock R$,30$ percent in Stock S$,$ and $20$ percent in Stock T$.$ The betas for these four stocks are $\mathrm{.}75,1\mathrm{.}90,1\mathrm{.}38,$ and $1\mathrm{.}16,$ respectively. What is the portfolio beta?