premise: Josef Groll (21 August 1813, Vilshofen an der Donau – 22 November 1887, Vilshofen) was a Bavarian brewer, best known for his invention of Pilsener beer, is known by some as "the Father of the Pils". The world's first-ever pale lager, his Pilsner Urquell was highly successful, and served as the inspiration for more than two-thirds of the beer produced in the world today.
hypothesis: Josef Groll was born in the summer.
reason: He was born in August, which is the summer. It may have been difficult because it requires knowing when summer is.