Simplify the following text for a Grade 7 native English-speaking person.
Original: A larger study started later by Franciszek Piper used timetables of train arrivals combined with deportation records to calculate 960,000 Jewish deaths and 140,000-150 ,000 ethnic Polish victims , along with 23,000 Roma and Sinti , a figure that has met with significant agreement from other scholars .
Simplified: Around the same time , Franciszek Piper used timetables of train arrivals and other records of sending out of people by the Nazis . He calculated 1.1 million Jewish deaths and 140,000-150 ,000 Polish victims , along with 23,000 Roma ( gypsies ) .