a. A detective in Detroit finds that 25 of the 62 guns used in crimes during the past week were sold by the same gun shop. This finding is statistically significant. Because there are many gun shops in the Detroit area, having 25 out of 62 guns come from the same shop seems unlikely to have occurred by chance.

b. In terms of the global average temperature, the 10 years from 2001–2010 were 10 of the 11 hottest years on record to that time, using a record going back to 1880. Having 10 of the 11 hottest years on record occur in a single decade is statistically significant. Indeed, having such a streak of hot years is very unlikely to have occurred by chance alone, and therefore provides significant evidence of a warming world.

c. The team with the worst win-loss record in basketball wins one game against the defending league champions. This one win is not statistically significant because although we expect a team with a poor win-loss record to lose most of its games, we also expect it to win occasionally, even against the defending league champions.