3.2 - Experimentation

Question 1

Validity

Answer 1

Variables controlled so that any measured effect is likely to be due to the independent variable

Question 2

Reliability

Answer 2

Consistent values in repeats and independent replicates

Question 3

Accuracy

Answer 3

Data or means of data sets are close to the true value

Question 4

Precision

Answer 4

Measured values are close to each other

Question 5

Pilot Study

Answer 5

Used to help plan procedures, assess validity and check techniques

Question 6

Independent Variable

Answer 6

The variable that is changed in a scientific experiment

Question 7

Dependent Variable

Answer 7

The variable that is being measured in a scientific experiment

Question 8

Control Group

Answer 8

Should always be included for comparison to the treatment group

Question 9

Qualitative Data

Answer 9

Subjective and descriptive

Question 10

Quantitative Data

Answer 10

Measured objectively usually with a numerical value

Question 11

Ranked data

Answer 11

Refers to the data transformation in which numerical values are replaced by their rank when the data are sorted from lowest to highest

Question 12

Simple Experiment

Answer 12

Measuring the effect of one independent variable on a dependent variable
It is easier to conduct and easier to control with respect to laboratory conditions

Question 13

Multifactorial Experiment

Answer 13

Involves a combination of more than one independent variable or combination of treatments

Question 14

Observational Studies

Answer 14

Researchers must use groups that already exist- and in this regard no truly independent variable exist
Good at detecting correlation
Less useful for determining causation they do not test a hypothesis

Question 15

Confounding Variables

Answer 15

• other variables besides the independent variables may affect the dependent variable
• these confounding variables must be held constant or at least monitored so that their effect on the results can be accounted for in analysis

Question 16

Randomised Block

Answer 16

• Can be used where confounding variables cannot easily be controlled
• Randomised blocks of treatment and control groups can be distributed in such a way that the influence of any confounding variable is likely to be the same across the treatment and control groups

Question 17

Control Results

Answer 17

• Used for comparison with the results of the treatment groups
• Positive and negative controls may be used

Question 18

Negative controls

Answer 18

• Provides results in the absence of treatment

Question 19

Positive Control

Answer 19

• A treatment that is included to check that the system can detect a positive result when it occurs

Question 20

Placebos

Answer 20

Can be included as a treatment without the presence of the independent variable being investigated

Question 21

Placebo Effect

Answer 21

Measurement change in the dependent variable as a result of a patient’s expectations rather than changes in the independent variable

Question 22

In Vitro

Answer 22

• Refers to the technique of performing a given procedure in a controlled environment outside of a living organism

Question 23

In Vivo

Answer 23

Refers to experimentation using a whole living organism

Question 24

Advantages of In Vivo

Answer 24

Results translate into a more precise understanding of what happens in a living organism

Question 25

Advantages of In Vitro

Answer 25

Less time consuming Less expensive

Question 26

Disadvantages of In Vivo

Answer 26

More expensive More time consuming

Question 27

Disadvantages of In Vitro

Answer 27

Results often do not translate into a precise understanding of what happens in a living organism

Question 28

Representative Sample

Answer 28

- It is impractical to measure every individual in a population and so a representative sample of the population should be selected - more variable populations require a larger sample size

Question 29

Random Sampling

Answer 29

- Members of the population have an equal chance of being selected - poor representation - No selection bias

Question 30

Systematic Sampling

Answer 30

- Members of a population are selected at regular intervals - More representative sample of the overall population - Not all members of the population have an equal chance of being selected it can be subjected to selection bias

Question 31

Stratified Sampling

Answer 31

- The population is divided into categories that are then sampled proportionally - Highly representative however setting up this form of sampling requires the researcher to know the proportions of each group prior to beginning