Simplify the following text for a Grade 7 native English-speaking person.
Original: In 1941 , during the Second World War , Hopkin was working as a civil servant at the Ministry of Health when selected by Winston Churchill to be part of the government 's statistical team .
Simplified: In 1941 , during the Second World War , Hopkin was working as a civil servant at the Ministry of Health . Winston Churchill chose him to be part of the government 's statistical team .