Sociology is the science of human relationships. Because nearly every part of our lives is shaped by our relationships with each other, sociology examines many different types of questions such as: How do diseases spread across social networks? How do new organizations succeed? How do businesses analyze market demand? Why do racial, ethnic, and gender inequalities persist despite so many attempts to redress them? What are the societal roots of criminal behavior? Sociologists use a variety of methods to study such questions ranging from quantitative survey techniques and experiments to in-depth interviewing and focus groups.