Chapter 1: Science Skills and Research Methods

Question 1

Aim

Answer 1

• A statement outlining the purpose of the investigation
• E.g. the aim of this investigation is to compare differences in the amount of sleep obtained by adolescents and elderly people

Question 2

Hypothesis

Answer 2

• Testable prediction of relationship between variables
• Must include:
  
  • IV and DV
  • Direction (e.g. strengthen, weaken, increase, decrease)
  • Comparison groups (generally the control group/s)

NOTE: The IV and DV do not need to be operationalised.

Question 3

Theories and models

Used interchangeably

Answer 3

• Interrelated concepts that attempt to explain observations and make predictions about future events

Question 4

Variables

Answer 4

• A variable is something that can change
• Independent – changed / manipulated
• Dependent – influenced by IV and is measured
• Controlled – variables other than the IV that are kept constant to ensure that changes in the DV are solely due to changes in the IV

Question 5

Extraneous vs confounding variables

Answer 5

• Extraneous – variable other than the IV that are not controlled and can have unwanted effects on the DV
• Confounding – variable other than the IV that has directly and systematically affected the DV
  
  • Can only be identified at the end of an experiment, as they
    must have consistently and predictably affected the results

Question 6

Participant-related variables

Individual participant differences / subject variables

Answer 6

• Characteristics of a study’s participants that may affect the results
• E.g. age, intelligence, and SES
• Extraneous / confounding when not a feature of the experiment

Question 7

Order effects

Answer 7

• Tendency for the order in which participants complete experimental conditions to affect their behaviour
• Practise – better performance in later conditions due to
  having done it before
• Fatigue – worse performance worse in later conditions due to being tired / bored from completing a prior task

Question 8

Placebo effects

Answer 8

• Response to inactive substances or treatments due to expectations or beliefs

Question 9

Experimenter effects

Experimenter bias

Answer 9

• Researcher’s expectations affect results of an experiment
• If they expect / wish to see a certain result, they can hold a confirmation bias when collecting data

Question 10

Situational variables

Answer 10

• Environmental factors that may affect the DV
• E.g. temperature, lighting, weather, time of day

Question 11

Population vs sample

Answer 11

• Population – entire group of interest from which the researcher draws a sample and seeks to generalise the results of their investigation
  
  • Members typically share characteristics (e.g. students)
• Sample – part of the population selected for research
  
  • Always smaller than a population
  • Should ideally accurately reflect entire population of interest

NOTE: The population is often referred to as the target population.

Question 12

Representative vs biased sample

Answer 12

• Representative – closely resembles the population from which it is drawn from
  
  • Sample has minimal errors in representing the population
  • Equal distribution of key participant characteristics
• Biased – does not adequately represent the key characteristics of its population

NOTE: Generally, the larger the sample, the more likely it is to be a representative.

Question 13

Sampling techniques

Answer 13

• Random – every member of the population is equally subject to being selected to be part of the sample
  
  • Poses minimal error in representing the population
• Stratified – sample consists of subgroups in the same proportion as they occur in the population of interest
  
  • Used to study behaviour / mental processes that tend to vary among different subgroups within a population
• Convenience – selecting members of the population that are easy to involve in the study
  
  • E.g. asking acquaintances or surveying people on the street

Question 14

Experimental and control groups

Answer 14

• Experimental – exposed to the independent variable
• Control – not exposed to the independent variable

Question 15

Random allocation

Answer 15

• Participants are equally as likely to be in one group as the other
• E.g. coin tossing or drawing names from a jar

Question 16

Between subjects (independent groups)

Experimental design

Answer 16

• Each participant is assigned to one group and provides only one piece of data
• Advantage – cost and time efficient
• Disadvantage – less control over participant differences

Question 17

Within subjects (repeated measures)

Answer 17

• Each participant is assigned to all groups and provides multiple pieces of data
• Advantage – individual participant differences can be controlled
• Disadvantages – performance can be influenced by fatigue or boredom (order effects)

Question 18

Mixed design

Answer 18

• Combines features of the between and within subjects design
• Advantage – takes advantage of the strengths of each design
• Disadvantage – limitations of both designs still exist

Question 19

Correlational study

Answer 19

• Researchers observe and measure the relationship between variables without any active control or manipulation of them
• Used when not ethical / possible to experimentally manipulate IV
• E.g. trauma, SA, drug misuse, age, gender

Question 20

Direction of correlation

Answer 20

• Positive – as one variable ↑, the other variable also ↑
• Negative – as one variable ↑, the other V ↓ (and vice versa)
• Zero – no relationship between the variables

Question 21

Interpreting deviations

Answer 21

• Higher standard deviation – more varied data
  
  • More outliers
• Lower standard deviation – less varied data
  
  • Less outliers

NOTE: Standard deviation is a method that best reveals the effect of outliers.

Question 22

Types of data

Answer 22

• Primary – collected first-hand by current researchers
• Secondary – collected earlier by different researchers
• Qualitative – non-numerical information (usually descriptions)
• Quantitative – numerical information
• Subjective – based on personal opinion
• Objective – measurable, verifiable and free from personal bias

Question 23

Repeatability and reproducibility

Answer 23

• Repeatability – how close measurements are to each other in identical conditions
  
  • Observer repeats experiment and produces same results
• Reproducibility – how close results are when the same variable is being measured under different conditions
  
  • Other people repeat experiment and produce same results

NOTE: The term ‘reliable’ no longer appears on the SD.

Question 24

Types of errors

Answer 24

• Random error – unpredictable (chance) variations in measurements that affect the precision of an experiment
• Systematic error – errors that are consistent and are due to fault in the method/equipment (affect the accuracy of a measurement and cannot be improved by repeating an experiment)
• Personal errors – mistakes made by the experimenter or researcher

Question 25

Research methods

Answer 25

• Experimental methods investigate what causes an outcome
• Correlational methods measure the relationship between variables
• Descriptive methods describe what is occuring
  
  • Observational studies (e.g. participant observations)
  • Self-reports (e.g. interviews, questionnaires)
  • Case studies (e.g. specific activities, behaviours, events or problems)

Question 26

Validity

Answer 26

• Internal – how successfully an experiment measures what it was intended to measure
• External – the extent to which research findings can be generalised to a greater population

Question 27

Robust findings

Answer 27

• Findings that will be produced again when the data is collected from another sample
• Can be linked to repeatability and reproducibility