Marine Science Practical Skills and Data Analysis

Flashcards covering experimental design, variables, measurement techniques, data presentation, graphing, sampling methods, and basic statistics from the marine science lecture notes.

In experimental planning, what is the difference between qualitative and quantitative observations?

Qualitative observations are descriptive (describing qualities); quantitative observations are numerical values.

What is a hypothesis?

A possible answer to the question “why?” that explains the observation.

What is a prediction in an experiment?

A statement of what you think will happen, linked to the hypothesis.

Independent variable (IV)

The variable being changed/manipulated in the experiment.

Dependent variable (DV)

The variable being measured in the experiment.

Control variables/constants

Variables not tested but kept the same; examples include temperature, CO2 concentration, O2 concentration, pH, light intensity.

Confounding variables

Variables that cannot be controlled but must be recorded because they can affect the dependent variable.

Control group/experiment

The group treated the same as the experimental group but without exposure to the independent variable.

Safety considerations in experiments

Hazards and risks must be identified and managed to protect participants and organisms.

Ethics in experiments

How living organisms are treated and how harm is avoided.

How can temperature be controlled in lab experiments?

With a water bath or thermostatically controlled bath and by using a thermometer to keep it constant.

How is pH controlled in experiments?

By using a buffer solution that maintains a constant pH.

How is oxygen introduced to solutions?

By bubbling it into the solution with an air pump.

How is carbon dioxide controlled?

Using a hydrogen carbonate solution to increase CO2 levels.

How is light intensity controlled?

By maintaining an equal distance from a light source.

Measuring liquids with a

graduated cylinder (smaller: syringe/pipette)

Measuring mass

Use a weighting scale or balance.

Measuring pH

Use a pH probe or universal indicator.

How many measurements for independent variable values should you aim for?

At least 5 values for the independent variable.

How many readings per value of the independent variable should be taken (trials)?

At least 3 readings (trials) at each value.

How should anomalous results be treated in calculations?

Identify them and exclude them from the mean calculations.

Data table structure for experiments

Columns for independent variable (with units) and dependent variable (with units); first column IV, second DV; include an average/mean column; use consistent decimal places.

General graph rules (axes and labels)

Independent variable on the X-axis; dependent variable on the Y-axis; both axes labeled with units; scale that uses about 75% of space.

Line graphs are used to show what kind of relationship?

Relationship between two continuous variables; points joined by straight lines; a best-fit line may be straight or curved.

What is the difference between histograms and bar charts?

Histograms show frequency data with continuous X-values and bars connected; Bar charts show a relationship between two variables with one continuous and gaps between bars for discontinuous data.