A variable represents the weight of a person. What type of data does it represent?
The weight of a person can be both comparable as well as it will change over time(Increase or decrease). So weight should be both ratio and Interval variable, right?
The "Ratio" level of measurement possesses (i) all properties of the "Interval" level; and (ii) in addition, it can accommodate absolute zero.
Therefore, the variable "weight" is considered as "Ratio" level [which already implies that this variable is "Interval"]
Similarly, the "Interval" level of measurement possesses all properties of the "Ordinal" level; and the "Ordinal" level possesses the property of the "Nominal" level.
Hope this helps.