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Investigation aim
The purpose of a study (includes IV, DV)
E.g To investigate the influence of caffeine consumption on memory performance.
Investigation question
The question that is to be solved by the study
E.g Does caffeine consumption influence memory performance?
Independent variable
The variable that is manipulated/altered in some way by the researcher to measure its effect on the DV
Dependent variable
The variable that is used to observe and measure the effects of the IV
Operationalising “does caffeine consumption increase memory performance?”
Operationalised IV: 5 cups of caffeine (in the form of coffee) or no cups of coffee
Operationalised DV: memory performance on a test of 20 questions
Controlled experiment
An investigation methodology that aims to test the effetcs of an IV on a DV, with all other variables controlled
Extraneous variables
Variables other than the independent variable that may have an unwanted effect on the dependent variable and results
Controlled variables
Variables that are held constant to ensure that the only influence on the dependent variable is the independent variable
Confounding variables
Unwanted variables that affect the DV and results in an investigation, and it cannot be determined whether the IV or ___ caused the change in the DV
Hypothesis
A statement outlining the probable outcomes of an investigation
Hypothesis template
It is hypothesised that (IV - experimental group) will have a (strength/direction) (DV) compared with (IV (control group)
E.g It is hypothesised that healthy adults who consume caffeine will show an increase memory performance compared with those who did not consume caffeine.
Population
The wider group of people that a study is investigating
Sample
The smaller group of people selected from the population who will be participants in the investigation
Stratified sampling
The population is first divided into subgroups, and participants are randomly selected from each subgroup, in the proportion that they appear in the population
Random sampling
Involves selecting participants from the population in such a way that each member of the population has an equal chance of being selected to participate in the study
Types of investigation methodologies
Controlled experiment, case study, classification & identification, correlation study, fieldwork, literature review, modelling & simulation, and product, process or system development
Allocation
Participants are divided between the experimental and control groups
Experimental group (in controlled experiment)
Exposed to the independent variable and receives the experimental treatment
Control group (in controlled experiment)
Forms a baseline level to compare with the experimental group
Random allocation
A method used that gives every member of the sample an equal opportunity of either being in the control or experimental group
Investigation designs
Between subjects design, within subjects design, mixed design
Between subjects design
When participants are randomly allocated to either the control or the experimental condition
Within subjects design
Involves all participants in the sample completing both the experimental and control conditions
Stratified sampling strengths and limitations
Strength: Representative of the population, improving external validity
Limitation: Difficult to obtain names of all members of the population
Random sampling strengths and limitations
Strength: Large samples are representative of the population, improving external validity
Limitation: Small samples may not be representative of population
Controlled experiment strengths and limitations
Strength: Can be repeated to test reliability of results
Limitation: Such strictly controlled conditions are difficult to maintain, so results can be affected by extraneous variables.
Between subjects design strengths and limitations
Strength: Most time-efficient
Limitation: Less control over the extraneous variables of participants, lowering validity
Within subjects design strengths and limitations
Strength: No varying extraneous variables of participants, improving validity
Limitation: More time consuming
Mixed design
Involves a combination of a between subjects design and a within subjects design
Mixed design strengths and limitations
Strength: Can test the effect of multiple independent variables
Limitation: Less control over participants’ prior knowledge
Case study
An investigation of a particular activity, behaviour, event or problem that contains a real or hypothetical situation and includes real-world complexities
Case study strengths and limitations
Strength: Used to study experiences where it would be unethical to conduct a controlled experiement
Limitation: One person / small group of people cannot be representative of a population, so low external validity
Classification and identification
A type of investigation that involves arranging phenomena, objects or events into a manageable sets, and recognising phenoma as beloning to a particular set.
Classification and identification strengths and limitations
Strength: Can help make predictions and inferences
Limitations: Can lead to stereotyping, prejudice or discrimination
Correlational study
Involve planned observation and recording of events and behaviours that have not been manipulated in order to understand the relationships existing between variables, identify which factors may be of greater importance and make predictions
Correlational study strengths and limitations
Strength: The direction and strength of a relationship between variables can be determined
Limitation: Correlation does not equal causation, so you cannot assume that one variable causes a change in the other
Fieldwork
Collecting information by observing and interacting with a selected environment
Fieldwork strengths and limitations
Strength: Natural settings are more likely to show behaviour that reflects real life
Limitation: Ethical concerns with the lack of informed consent in some cases
Literature review
Involves collating and analysing secondary data findings and/or viewpoints
Modelling and simulation
Involves constructing and/or manipulating a physical or conceptual model of a system
Product, process and system development
Involves the design of a product, a process or a system to meet a human need
Ethical concepts
Integrity, justice, non-maleficence, beneficence, respect
Integrity
The commitment to searching for knowledge and understanding, and the honest reporting of all sources of information and results
Justice
Involves the moral obligation to ensure that competing claims are considered fairly, that there is no unfair burden on a particular group from an action, and that there is fair distribution and access to the benefits of an action
Beneficence
The commitment to maximising benefits and minimising the risks and harms
Non-maleficence
To avoid causing harm
Respect
Involves considering the value of living things, giving due regard, and considering the capacity of living things to make their own decisions
Ethical guidelines
Confidentiality, voluntary participation, informed consent, withdrawal rights, use of deception, debriefing
Confidentiality
Ensuring that participants remain anonymous, and their personal information is kept private, protected and secure throughout the study
Voluntary participation
Ensures that each participant freely agrees to participate in a study, with no pressure or coercion
Informed consent procedures
Conducted before a study begins, where participants agree to participate in the research after they have received all the details of the investigation including the nature and purpose, methods of data collection and potential risks
Withdrawal rights
Ensure that participants are free to discontinue their involvement in a study without receiving a penalty
Debriefing
Conducted at the end of the study and is when participants are informed of the true aims, results and conclusions of the study
Deception
Involves withholding the true nature of the study from participants if their knowledge of the true purpose may affect their behaviour and the subsequent validity of the investigation
Primary data
Collected through first-hand experience for an intended purpose
Secondary data
Obtained second hand through research conducted or data collected by another person for another purpose. Secondary data may be used when it is not possible to collect primary data because of time or cost, or if participants are unavailable
Qualitative data
Describes characteristics and qualities.
Quantitative data
Involves measurable values and quantities and can be compared on a numerical scale.
Percentage
Part of a whole, expressed as a proportion out of 100
Percentage change
A calculation of the degree of change in a value over time
- a positive percentage change indicates a percentage increase, a negative percentage change indicates a percentage decrease
Measures of central tendency
A category of statistics that describe the central value of a set of data - mean, median, mode
Mean
The average value of a set of data
( sum of all data points / no. of data points )
Median
The middle value in an ordered set of data
Mode
The value that occurs the most frequently within a set of data
Measures of variability
A category of statistics that describe the distribution of data
Standard deviation
Shows the spread of the data around the mean. It shows how close each data value lies to the average, or how far spread out they are – in other words, how much the values vary.
Ways of organising and presenting data
Charts & graphs (bar charts and line graphs), tables
True value
The value, or range of values, that would be found if the quantity could be measured perfectly
Accuracy
How close a measurement is to the true value of the quantity being measured
Precision
Refers to how close a set of measurement values are to each other. It describes how exact a measurement is, and how much a value agrees or is consistent within a set of values that were measured under the same conditions.
Repeatability
How close successive measurements of the same quantity are when carried out under the same conditions
Reproducibility
How close measurements of the same quantity are when carried out under different conditions
Reproducibility vs repeatability
Repeatability refers to the extent to which a study's findings can be replicated or repeated under similar conditions, typically by the same research team. Repeatability assesses the consistency and stability of a study's results over time and with the same research procedures.
Reproducibility refers to the extent to which a study's findings can be independently obtained by other researchers using different methods, instruments, or settings. Reproducibility assesses the robustness and generalizability of a study's results across different contexts.
Validity
Refers to whether a measurement measures what it is supposed to be measuring
Internal validity
Refers to a study investigating what it sets out or claims to investigate
External validity
Refers to whether the results of the research can be applied to similar individuals in a different setting
Personal errors
Include mistakes, miscalculations and observer errors made when conducting research.
Measurement errors
The difference between the measured value and the true value of what is being measured - systematic errors and random errors.
Systemic errors
Affect the accuracy of a measurement by causing readings to differ from the true value by a consistent amount or by the same proportion each time a measurement is made.
Random errors
Affect the precision of a measurement by creating unpredictable variations in the measurement process; they result in a spread of readings.
Uncertainty
Refers to a lack of exact knowledge of the value being measured
Contradictory data
Incorrect data
Incomplete data
Missing data - questions without answers or variables without observations
Outliers
Values that lie a long way from other results