Answer
Not necessarily. If the coin is really fair, the estimate probability will approach 50% after tossing the coin a large number of times.
Work Step by Step
Suppose the coin is tossed another 900 times and we get 450 heads. Now, we have:
$P(heads)=\frac{fr(heads)}{N}=\frac{70+450}{100+900}=\frac{520}{1000}=0.52\approx0.50$
