Velocities of four gas molecules are $2 m/sec, 3 m/sec, -4 m/sec and -1 m/sec$ respectively then which of the following statement is /are correct ?

$\begin{array}{l}{V}_{mean}=\frac{V_1+V_{}+V_3+V_4}{4}{V}_{speed}=\frac{2+3+4+1}{4}\\ =\frac{2+3-4-1}{2}=0=2.5m/\sec \\ V_{mean}^2=\frac{V_1^2+V_2^2+V_3^2+V_4^2}{4}=7.5m^2/{\sec }^2\\ V_{rms}=\frac{\sqrt{V_1^2+V_2^2+V_3^2+V_4^2}}{4}=2.74m/\sec \end{array}$