C3

Question 1

A hypothesis must:

Answer 1

• Have an independent variable (IV)
• Have a dependent variable (DV)
• Be testable
• Be measurable
• Have direction
• Be a statement (not a question)

Question 2

The Independent Variable is:

Answer 2

What is CHANGED

Question 3

The Dependent Variable is:

Answer 3

What CHANGES

Question 4

When writing a procedure for an exam-style question, you must:

Answer 4

1. State the IV and how it is changed
2. State the DV and how it is measured
3. describe apparatus and method in dot points
4. Indicate sample sizes and quantities of materials (avoid “amount”)
5. State 4 controlled variables and why they must be kept controlled
6. indicate what part of the experiment is the control group (if required)
7. Uncontrolled variables (if relevant)
8. Ethical considerations

Question 5

How can an experiment rule out the risk of placebos

Answer 5

Single Blind - participants do not know which group they are part of
Double Blind - participants and observers do not know which groups the participants are part of

Question 6

What are the main Ethical considerations in Biology

Answer 6

1. Integrity
2. Justice
3. Beneficence
4. Non-maleficence - benefits outweigh the harm
5. Respect

Question 7

When Human trials are conducted, it is important to:

Answer 7

• Obtain INFORMED consent
• Provide care for any negative effects
• Access to findings
• The right to withdraw

Question 8

When looking for possible sources of error in procedures, consider:

Answer 8

1. Accuracy of equipment
2. Possibility of human error
3. Sample size
4. Replicates of the procedure

Question 9

When asked to “evaluate” an experiment, consider:

Answer 9

1. Validity - Control group, consideration of fixed variables, placebo, anything else that may affect the accuracy of results
2. Reliability - Sample size, number of trials, repeatability, any other factor that can affect consistency/precision of results
3. Ethics - any potential harm (Human, Organism, Environment), Consent, Ethics approvals

• 1 mark for limitation and 1 mark for improvement

Question 10

What are the 5 types of error?

Answer 10

1. Random Error - Random, uncontrollable errors such as the human eye measuring using a messing cylinder
2. Systematic Error - reduces accuracy, can be due to faulty equipment and errors in the apparatus
3. Outliers - a data point that is well outside of the rest of the data (should be excluded from tables and lines of best fit) CAN BE EXPLAINED BY ERROR
4. Annomoly - a data point that fits outside of the expected result. exclude from averages.
5. Uncertainty - when a measurement is unreliable