claim: When you account for all of the costs associated with burning coal and other fossil fuels, like air pollution and health effects, in reality they are significantly more expensive than most renewable energy sources.
evidence: If two events, A and B are independent then the joint probability is P ( A  and  B ) = P ( A ∩ B ) = P ( A ) P ( B ) , {\displaystyle P(A{\mbox{ and }}B)=P(A\cap B)=P(A)P(B),\,} for example, if two coins are flipped the chance of both being heads is 1 2 × 1 2 = 1 4 {\displaystyle {\tfrac {1}{2}}\times {\tfrac {1}{2}}={\tfrac {1}{4}}} .