What was the original MMPI standardized on?

The original Minnesota Multiphasic Personality Inventory (MMPI) was standardized on a sample of individuals from the general population of Minnesota, primarily in the late 1930s and early 1940s. The sample included various Demographics, such as age, gender, and socioeconomic status, but was predominantly composed of White individuals. This standardization aimed to create a reliable assessment tool for identifying psychological disorders. Subsequent versions, like the MMPI-2, have expanded the normative sample to improve representativeness.