It is relatively easy to analytically determine the signal metrics for a continuous-time sinusoidal signal.
Over one period of a sinusoid, the signal mean is zero.
The signal power of a sinusoid can be determined by integrating over one period:
The plot below shows the signal metrics calculated for a discrete-time sinusoidal signal. Note that these values were calculated over the entire signal length, which is not an exact integer number of periods.