claim: When stomata-derived CO2 (red) is compared to ice core-derived CO2 (blue), the stomata generally show much more variability in the atmospheric CO2 level and often show levels much higher than the ice cores.
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}}} .