Which of the following best describes continuous variables?

Continuous variables are defined as values that can take on an infinite number of possible values within a given range. This means that they are not restricted to fixed increments and can represent fractions or decimals, allowing for a very precise measurement. For instance, measurements such as height, weight, temperature, and time are all examples of continuous variables because they can be measured to any desired degree of accuracy and can vary seamlessly.

The other options do not accurately describe the nature of continuous variables. Some values that can be counted, as mentioned in one option, refer to discrete variables, which are distinct and separate values, often integers. Furthermore, categorical outcomes, represented in another choice, are related to nominal or ordinal data, which describe characteristics or categories rather than numerical quantities. Values with fixed numerical intervals pertain to certain types of quantitative data that can only take on specific values, again diverging from the continuous aspect that allows for infinite possibilities within a range. Thus, the description of continuous variables as values that are uncountable and can extend infinitely is the most accurate characterization.