UNIT 0: EXPERIMENTAL DESIGN & STATISTICAL ANALYSIS

Null Hypothesis

there is no significant difference in the number of (dependent variable) in (independent variable). Any difference is due to chance

Independent Variable

a variable you control

Dependent Variable

the result due to the manipulation

Constant Group

factors that remain unchanged (temperature, time)

Control Group

serves as a standard of comparison (does not receive manipulation)

Negative Control

unexposed to experimental treatment; shows what no effect looks like

Positive Control

given a treatment w/ a known effect; shows that experiment works

Controlled Experiments

test one independent variable at a time, comparing each

Standardization

keeping sample sizes equal ensures fair comparison b/w samples to show results are due to treatment, and not uneven group sizes

Why is collecting data over time important?

collecting data over time identify rates, trends, or unexpected events during experiment

Chi Square Statistic Rule

if the x-value is more than the critical value, the null hypothesis is rejected

What happens if the error bars overlap?

results is not significantly different (supports null hypothesis)

Why is lower standard deviation better?

less variable variation there is in the data and most trustworthy that data is