Variables
The factor in an experiment that a scientist deliberately changes.
Independent variable
The group that receives no treatment and is used for comparison.
Control group
Is the independent variable the x or y axis?
x axis
What is cohesion and adhesion?
Cohesion is water sticking to itself, and adhesion is water sticking to other surfaces.
What does the chi-square test determine
This test is used to determine if observed data fits expected data.
The variable that is measured or observed as a result of the experiment.
Dependent variable
A condition kept the same across all groups to ensure a fair test.
Constant (controlled condition)
“A line drawn through data points to show the overall trend.”
best-fit line
Why does ice float on water?
Ice floats on liquid water because it is less dense.
What is the observed value (O)?
This part of the chi-square formula represents the data you actually collected in your experiment.
A variable that must remain constant to avoid influencing the results.
Controlled variable (constant)
The term for a group that receives a fake or inactive treatment.
Placebo group
“The type of graph best for showing change over time.”
line graph
How does sweating (evaporation of water) help regulate body temperature?
This process cools the body because water molecules take heat energy with them as they change from liquid to gas.
What is the expected value (E)?
This part of the chi-square formula represents the data you expect to see if your hypothesis is correct.
Type of variable represented on the x-axis of a graph.
Independent variable
Why having a control group increases experiment validity.
It shows whether the treatment actually causes the effect / provides a baseline
In the fermentation lab, what was the independent variable?
The type of suger
Why is water called the “universal solvent”?
Water is called this because it can dissolve many substances, such as salts and sugars, which is essential for transport in blood and cells.
What are the degrees of freedom?
This tells you how many categories or groups are independent in your chi-square test and is used when finding the critical value.
A variable that is influenced by multiple factors but not intentionally manipulated; often accounted for through statistical controls.
Confounding variable
Name three things that had to stay the same in the Pillbug lab
Light, Pillbug type, and Temperature
What was the dependent variable in the pill but lab?
How many pill bugs were on each side.
What is high specific heat?
This property of water allows it to absorb or release large amounts of heat with only a small change in temperature, helping organisms maintain stable internal conditions.
What is the limitation of chi-square regarding effect size or strength of association?
A chi-square test cannot tell you how strong a relationship is, only whether the observed and expected data differ significantly.