8.
下列命题正确的个数是\((\) \()\)
\({{p}_{1}}:\)若\(m,n\)是两条不同的直线,\(\alpha ,\beta \)是两个不同的平面,若\(m{\parallel }\alpha ,n{\parallel }\alpha ,m\subset \beta ,n\subset \beta \),则\(\alpha {\parallel }\beta \)
\({{p}_{2}}:\)命题“\(\exists {{x}_{0}}\in \mathrm{R},x_{0}^{3}-x_{0}^{2}+1\leqslant 0\)”的否定是“\(\forall x\in R,{{x}^{3}}-{{x}^{2}}+1\geqslant 0\)”
\({{p}_{3}}:\)函数\(y=\sin (\omega x+\dfrac{\pi }{6})\)在\(x=2\)处取得最大值,则正数\(\omega \)的最小值为\(\dfrac{\pi }{6}\)
\({{p}_{4}}:\)若随机变量\(Z\tilde{\ }N\left( \mu ,{{\sigma }^{2}} \right)\),则\(P\left( \mu -\sigma < Z\leqslant \mu +\sigma \right)=0.6826\),\(P\left( \mu -2\sigma < Z\leqslant \mu +2\sigma \right)=0.9544\)\(.\)已知随机变量\(X\tilde{\ }N\left( 6,4 \right)\),则\(P\left( 2 < X\leqslant 8 \right)=0.8185\)