Can continuous variables be negative? - Answers

Yes, continuous variables can be negative. For example, we generally treat temperature in as a continuous variable and temperature in the Fahrenheit or Celsius scales can have negative values. Considerably more explanation is below.Conventionally, there are three types of variables, which can go by names other than the ones I list:CategoricalDiscreteContinuousCategorical variables (which can be further sub-classified) are variables that aren't numeric in nature. So if you record the colors of a traffic light or the gender of a study subject, those are categorical in nature.Discrete variables are those that are numeric in nature, but which have a limited resolution with which we can measure them. Common examples are counts, which can only be integers, never decimals. So if you record the number of unfilled soda cans that come out of a filling machine, you are getting discrete data.Continuous variables can theoretically be measured with infinite precision. To be very technical, it's almost impossible to record continuous data because you'd have to be able to record an infinite number of decimal points, but in practice we can treat many different kinds of data as continuous. For example, US Dollars are conventionally only measured to two decimal points, but we can usually treat them as continuous. It turns out that for practical purposes, the key to treating data as continuous is to not have repeated values. Even count data, which are discrete by definition, can be treated as continuous in many circumstances. Look in a statistics reference for information about the normal approximation to the binomial distribution or the normal approximation to the Poisson distribution for more information.