An interval scale is one where there is order and the difference between two values is meaningful. Examples of interval variables include: temperature (Farenheit), temperature (Celcius), pH, SAT score (200-800), credit score (300-850).
An interval variable has values whose differences are interpretable, but it does not have a true zero. ...A good example is temperature in centigrade degrees. data on an interval scale can be added and subtracted but cannot be meaningfully multiplied or divided
