– Viscosity: the consistency of a fluid
High viscosity: thicker, slower flowing liquid
Low viscosity: thinner, faster flowing liquid

– The basics of data science:
The independent variable (X) affects the dependent variable (Y).
If you measure the effect of tutoring hours (X) on ACT score (Y), tutoring hours is independent variable and the ACT score is the dependent variable.
The independent variable is graphed on the x axis and the dependent variable is graphed on the y axis.

– What is a control group? If you are trying to measure the impact of a medication on blood pressure readings, you would have a treatment and a control group. The control group includes people who are not given the new medication. The treatment group is given the medication. In a randomized trial, you randomly assign participants to one of the two groups (treatment or control).

– What does it mean if x and y are directly related (directly proportional)? As x increases, y increases. As x decreases, y decreases.
What about inversely related (indirectly proportional)? If x increases, y decreases and vice versa. Example: Carbon emissions and air quality.