Yearly income is considered a b) continuous ratio variable. This classification stems from several key traits of income data.
Firstly, continuous variables can take on any value within a range. In the case of yearly income, it can be any non-negative value, including decimals, representing the possible salaries or earnings a person can have.
Secondly, income has a true zero point, indicating the absence of income, which further classifies it as a ratio variable. This aspect allows for meaningful comparisons and calculations, such as determining how many times greater one income is compared to another.
On the other hand, options like nominal and ordinal refer to categorical data types that don’t measure quantities. Discrete variables are countable and involve whole numbers, but income can include fractional values, which makes it a continuous measure.
In summary, yearly income falls into the category of continuous ratio because it holds numerical significance, has a true zero point, and can take on an infinite number of values within a range.