'I accept every time I get in my car, there's a 20% chance I could die'. It's a line from the Formula 1 hit film, Rush. Spoken by racing driver Niki Lauda's character. Formula 1 was certainly a dangerous sport during the 1970s, but was it really that dangerous? Tim Harford and Hannah Barnes look at the data. Plus, is it true that it takes 1,000 years for a plastic bag to degrade? It's a popular claim, but More or Less finds the environmental facts about plastic bags are much less certain than that statistic suggests. This edition was first broadcast on the BBC World Service.