Most statisticians also specialize in another subject area.
Some are generalists who interact with several areas of application. A substantial fraction of the concentrators also major in another field. This could be anything from Biology to Economics or History. Their program is mostly determined by the requirements of the other concentration. Apart from being able to design and carry out their own quantitative investigations, an additional asset of a statistics background is to be able to understand the validity of claims made in studies carried out by others.