Numerical data, as the name suggests, is expressed in numbers and not in any other descriptive form.
A numerical factor in biology could be the concentration of a certain chemical in a solution. This concentration can take any value within a range. By manipulating the concentration of the chemical and observing the resulting effects, researchers can gain insights into how this chemical impacts the behaviour of biological systems.
For example, if you are performing a media optimisation experiment and want to investigate the effect that the concentration of the carbon source, Glucose, has on the performance of your media, then this should be treated as a numerical factor. The factor, Glucose, can be prepared at values between the lower and upper levels you want to investigate.
In Synthace, we handle your factors automatically based on the context within which they are defined. Factors that are applied to the Total Mixture Volume parameter in the Make Mixtures or Mix Onto elements are treated as numerical, automatically (Figure 1). Similarly, factors that specify specific liquid components in a mixture, within the Mixture Composition parameter in the Make Mixtures or Mix Onto elements, will be treated as numerical (Figure 1).
Figure 1. Examples of numerical factors in Synthace. The most common numerical factors described in Synthace workflows are the final volume of a reaction or the concentration/volume contributions of specific liquid components to a mixture.
In Space Filling DOE designs, numerical factors can be sampled continuously between the lower and upper levels, or discretely at the specific levels you have defined (Figure 2).
Figure 2. Sampling numerical factors continuously or discretely in Space Filling DOE designs. Space filling DOE designs are extremely useful for factor screening or characterisation of your experimental space and when you have little prior knowledge regarding the shape of your space. Sampling a range will give you better insight into the shape of your experimental space, but will cost you more runs. Sampling discretely will save you runs, but with no prior knowledge you could draw a misleading conclusion (dashed line). However, with some prior knowledge, you can set levels appropriately and save runs, while still capturing the shape of the space appropriately (solid line).
To learn how to define a numerical factor in a mixture, click here.
To learn how to define a numerical volume factor, click here.
To learn how to define a custom numerical factor, click here.
To learn about other factor types, click here.