After his graduation he joined Eirene – International Christian Service for Peace[1] and worked as volunteer with troubled teenagers in Ohio and with a community serving the homeless in Los Angeles.

Back to academic life, he obtained a master's degree at the University of Southern California in 1986 and his PhD in applied mathematics in 1988.

He then worked in the US and Germany as a research fellow and obtained his German Habilitation in mathematics education from Ludwigsburg University in 1998.

Recently he is best known for his contributions in Statistics Education, investigating students’ comprehension of randomness and variability (Engel & Sedlmeier 2005)[4] and introducing computer intensive methods, based, for instance, on bootstrap procedures (Engel & Grübel, 2008).

[7] He has been an active member of the International Association for Statistical Education (IASE) and a coordinator of ProCivicStat (www.procivicstat.org), a strategic Partnership sponsored under the Erasmus+ program of the EU, aimed and empowering people to understand statistics about society.