Ecology - Biol 333 Lab Exam

Front 1

Hypothesis Vs Theory

Back 1

Hypothesis is a plausible explanation for a question before it's been rigorously tested.
A theory has withstood testing and is generally accepted to explain something. Modern tests can't disprove it.

Front 2

Null Vs Alternative Hypothesis

Back 2

Null = Treatment has no effect, observed results are the same as would be due to chance
Alternative = There is an effect, what's being tested by the person.

Front 3

Continuous Vs Categorical

Back 3

Continuous = Temperature, height
Categorical = Male/female, fenced/unfenced, drugs/no drugs.

Front 4

Dependent Variable vs independent

Back 4

Think - Is one variable likely to affected by the other? Dependent = Response, independent = predictor
Independent = X axis of graph
Dependent = Y axis

Front 5

Treatment Vs Treatment Level

Back 5

Treatment = Categorical independent variables
Density (low med high) herbivory (fenced, unfenced)
Treatment Level = alternative states of a particular treatment

Front 6

Meaning of P Values

Back 6

Test performed on a data set.
Ranges from 0-1
Significant if less than .05
P=.05 means 5% chance the differences observed between groups are due to chance
95% confidence that observed results are due to predictor variable

Front 7

Descriptive Studies

Back 7

Observational studies, effective for spotting trends in a situation and helpful for generating additional hypothesis on which further research can be based

Front 8

Comparative Study
Natural Experiment
Observational Study

Back 8

Draws inferences about possible effects of treatments on subjects where the assignment of treated groups vs control groups is outside the control of the investigator.

Front 9

Multiple Comparison Test

Back 9

When there are 2+ treatment levels, an ANOVA will say the treatment had a significant OVERALL effect. However, the treatment levels may not be different from each other. A Multiple Comparison Test will tell if there's differences among all possible pairs of means.