Precisely! In this case, the probability that you will get a Head is a 100%. So, how many ever times you toss it, you will always get a Head.

Similarly, imagine an electron E. Let us write $$E = \left( \frac{70}{100} \times \uparrow \right)+ \left( \frac{30}{100} \times \downarrow \right)$$ to represent that there is a 70% chance of us measuring a spin of $$+\frac{1}{2}$$ $$\left( \textrm{that is, spin} \uparrow \right)$$ and a 30% chance of us measuring a spin of $$-\frac{1}{2}$$ $$\left( \textrm{that is, spin} \downarrow \right)$$.