Målestillingsnivåer

Målestillingsnivåer refers to the different scales or levels at which data can be measured. Understanding these levels is crucial for choosing appropriate statistical methods and for correctly interpreting the results of data analysis. There are generally considered to be four main målestillingsnivåer: nominal, ordinal, interval, and ratio.

Nominal level data is the simplest type of measurement. It involves categorizing data into distinct groups where there is no inherent order or ranking. Examples include gender (male, female), eye color (blue, brown, green), or types of fruit (apple, banana, orange). Operations like counting frequencies are appropriate, but mathematical operations like addition or subtraction are not meaningful.

Ordinal level data, also known as ranked data, involves categories that can be ordered or ranked. However, the intervals between these ranks are not necessarily equal or quantifiable. Examples include survey responses like "disagree," "neutral," "agree," or satisfaction ratings like "poor," "fair," "good," "excellent." While we know one category is higher than another, we cannot say by how much.

Interval level data has ordered categories with equal intervals between them. This means that the difference between two values is meaningful. However, interval data lacks a true zero point, meaning that zero does not represent the absence of the quantity being measured. An example is temperature in Celsius or Fahrenheit. A temperature of 20 degrees is warmer than 10 degrees, and the difference is 10 degrees, but zero degrees Celsius or Fahrenheit does not mean there is no temperature.

Ratio level data is the most informative level. It has ordered categories with equal intervals and a true zero point. This true zero allows for meaningful statements about ratios. For instance, height, weight, income, and age are ratio data. A person who is 2 meters tall is twice as tall as someone who is 1 meter tall. Zero height or zero weight signifies the absence of that attribute. Statistical operations such as addition, subtraction, multiplication, and division are all applicable to ratio data.