Question

which of the following were independent variables in study 2?
a type of mineral added and viscosity only
b type of mineral added and temperature only
c type of mineral added, temperature, and amount of mineral added only
d type of mineral added, temperature, amount of mineral added, and viscosity

Explanation:

To determine independent variables, we recall that independent variables are manipulated or controlled in a study, while dependent variables are measured. Viscosity is typically a dependent variable (measured outcome), so options A and D are out. The independent variables here should be the factors controlled: type of mineral added, temperature, and amount of mineral added (these are manipulated), so option C is correct.

Answer:

C. Type of mineral added, temperature, and amount of mineral added only