Scale types refer to the different ways in which data can be measured and categorized. The main types include nominal, ordinal, interval, and ratio scales. Nominal scales classify data into distinct categories without any order, while ordinal scales rank data in a specific order. Interval scales have equal distances between values but lack a true zero point, and ratio scales possess both equal intervals and a true zero, allowing for meaningful comparisons. Understanding these scale types is essential for selecting appropriate statistical methods and accurately interpreting data. Each scale type influences how data can be analyzed and what conclusions can be drawn. For example, mean calculations are suitable for interval and ratio scales, but not for nominal or ordinal scales.