  A simple way, accessible to undergraduates, is given to understand
measurements in quantum mechanics. The ensemble interpretation of quantum
mechanics is natural and provides this simple access to the measurement
problem. This paper explains measurement in terms of this relatively young
interpretation, first made rigorous by L. Ballentine starting in the 1970's.
Its facility is demonstrated through a detailed explication of the Wigner
Friend argument using the Stern Gerlach experiment. Following a recent
textbook, this approach is developed further through analysis of free particle
states as well as the Schrodinger cat paradox. Some pitfalls of the Copenhagen
interpretation are drawn out.
