D. How many variables of interest are in our experimental design? Are
these factors (categorical) or continuous? If factors, how many levels
are there? List out the levels for each factor. (1 pt)
D. How many variables of interest are in our experimental design? Are
these factors (categorical) or continuous? If factors, how many levels
are there? List out the levels for each factor. (1 pt)

In our experimental design, we have three variables of interest:

1. Temperature: This is a continuous variable as it can take any value within a certain range.

2. pH: This is also a continuous variable as it can take any value within a certain range.

3. Presence of a specific enzyme: This is a factor variable with two levels: Yes (1) or No (0). We do not have different levels for this factor.

So, in summary:
- Temperature: Continuous, range Tmin to Tmax
- pH: Continuous, range pHmin to pHmax
- Presence of enzyme: Factor with 2 levels: Yes, No
Based on the experimental design, there are 3 variables of interest:

1. **Type of fertilizer** (factor): This is a categorical variable with 3 levels:
	* Organic fertilizer
	* Chemical fertilizer
	* No fertilizer (control)
2. **Amount of water** (factor): This is a categorical variable with 2 levels:
	* High water
	* Low water
3. **Soil type** (factor): This is a categorical variable with 2 levels:
	* Clay soil
	* Sandy soil

All three variables are factors, which means they are categorical variables with distinct levels. There are no continuous variables in this experimental design.