Key Science Skills

Population

The larger group from which a sample is selected, to which the researcher will seek to apply/generalise the results

Sample

Participants who are selected and used in the research that are part or a subset of a larger group

Ideal sample of people

Reflects the population in regard to characteristics that are relevant to the study, so that the results can be generalised back to the population

Representative Sample

Represents the population correctly

Characteristics of a Representative Sample

• A relatively large sample size

• Minimal to no bias

• Relevant characteristics are in the same proportion as is in the population

Sampling Techniques

The process through which participants are selected from the population of interest

Scientific Method

The steps taken to conduct the investigation

Investigation Methodologies

Specific techniques used to collect and analyse data in an investigation

Cycle of Models and Theories

Models and theories are changed and redesigned as observations from recent findings are uncovered. This then prompts more questions to form, stimulating more research and experiments to be conducted, which in turn updates current or forms new models and theories.

Advantage of Models

It creates a common language that can be used to collaborate and communicate to form solutions to shared problems

Variable

Something that can change in amount and/or type and is measurable

Random sampling

A form of sampling where every member of the population has an equal chance of being selected

Benefit of Random sampling

It reduces bias and is therefore more likely to be representative

Limitations of random sampling

• can be time-consuming and difficult to identify every member of the population to ensure everyone has an equal chance of being selected

• for smaller samples, it may not be representative

Stratified Sampling

When a population is divided into groups based on relevant characteristics, and participants are selected from each group in proportion to how they appear in the population

Benefit of Stratiified Sampling

It is more likely than other techniques to produce a sample that is representative of the population

Limitations of Stratified Sampling

• sometimes, strata (groups) can be difficult to define

• can be time-consuming and difficult to ensure the strata are developed accurately and that participants are selected in the correct proportions

Hypothesis

A testable prediction about the relationship between two or more variables

What does a hypothesis start with?

It is hypothesised that…

Components needed for a good hypothesis

I: IV

P: Prediction of relationship (direction)

O: Operationalise variables

D: DV

Aim

The purpose of a study

Independent variable

The variable that is systematically changed

Which axis in a graph represents the independent variable?

X-axis

Dependent Variable

The variable used to measure the effects of the IV

Which axis in a graph represents the dependent variable?

Y-axis

Controlled variable

Variables that could potentially have an effect on the DV and thus needs to remain constant to remove the said effects

Operationalising variables

Defining precisely how the variables will be manipulated or measured in terms of procedures, actions, or processes to ensure IV and DV are testable and therefore that the reserach hypothesis are testable.

Advantage of operationalising variables

It avoids experimenter biases and differences that can affect the results in an undesired way

Case study

An investigation that contains a real or hypothetical investigation an includes the complexities encountered in the reeal world

Forms of case studies

• historical: real event in the past

• real situation or role play: plausible recommendations are made

• problem-solving: development of a new design

Classification (as part of Classification and Identification)

Determining which sets of characteristics are desired for a study

Identification (as part of Classification and Identification)

Recognising phenomena as belonging to a certain or new set

Advantages of Classification and Identification

• forms a common language about scientific which helps to simplify, explain, and describe

• prompts targeted solutions or interventions

• theories can be formed about labelled phenomena

Limitations of Classification and Identification

• over-simplification can lead to overgeneralisation

• a label and language that is inaccurate can lead to bias or perpetuate stereotypes and prejudice

Types of highly detailed in-depth information gathered in case studies

• biographical history

• psychological and biological data

• environmental information

• qualitative and quantitative data

Advantages of case studies

• highly detailed

• allows rare phenomena to be explained in-depth

• can be combined with other scientific methodologies

Disadvantages of case studies

• cannot be generalised to the public, leading to lower external validity

• more prone to researcher bias/errors as there are often one or few researchers

• difficult to determine causal relationships

• time-consuming

Controlled experiment

Investigation of the relationship between one or more IV’s and a DV, controlling all other variables

Advantages of a controlled experiment

• a causal relationship can be inferred between, and draw conclusions about, specific variables

• control over conditions and variables, leading to higher repeatability which then means the results can be checked

• control over conditions and variables also leads to the prevention of extraneous and confounding variables

• hypotheses can be tested quickly in comparison to waiting in a natural experiment

Limitations of a controlled experiment

• may not be reflective of real life (low generalisability as real life is not in lab settings)

• open to researcher error or experimenter effects

• time consuming and expensive

Correlational study

Observation of events or behaviours that have not been manipulated/controlled for an understanding of the relationships/associations that exist between variables

The process of correlational studies

1. find the relationship

2. describe the relationship

3. make predictions based on the relationship

Types of correlational studies

• fieldwork

• archival data

• ovservational studies

• surveys

Advantages of Correlational studies

• can identify which factors may be of greater significance to some phenomena

• don’t need manipulation of variables

• can prompt ideas for future hypotheses and research, such as identifying the cause

• information about the relationship between variables

• in naturalistic settings, meaning that it has greater applicability and therefore external validity

Limitations of Correlational studies

• can’t show conclusions about cause and effect

• likely to be influenced by extraneous variables

Fieldwork

observing and interacting in a natural setting, based on the inquiry/investigation of an issue, to determine the correlation between variables

Advantages of fieldwork

• applicable to the real world as it is conducted in a nautralistic setting

• produces detailed data

• can use a broad range of methods

• can occur over a long time, making previously unknown information clear

Limitations of fieldwork

• time-consuming and expensive

• (generally) no cause and effect

• difficult to replicate, meaning there is low repeatability and reproducibility

• difficult to control environment and extraneous variables

Literature review

Collection and analysis of secondary data to generate primary data

When is a literature review typically conducted?

Often done before conducting a new study to redefine the topic to address gaps of knowledge in the scholarship

Meta-analysis

Large scale literature review

Advantages of literature review