Describe a positively skewed distribution.

Most of the scores bunch up at the low end of the scale and a long tail stretches away towards the high values on the right.

A class sits a test that almost everyone finds far too hard. What shape will the distribution of marks take?

It will be positively skewed, because the great majority of marks cluster near the bottom of the scale with only a few higher marks trailing off to the right.

Describe a negatively skewed distribution.

Most of the scores bunch up at the high end of the scale and a long tail stretches away towards the low values on the left.

In a negative skew, how do the mean, the median and the mode compare?

The mean is the lowest of the three because it is pulled down by the few very low scores, the median lies between them, and the mode is the highest.

An easy test produces a ceiling effect. Which skew results, and why?

A negative skew results, because nearly everyone scores at or close to the maximum, leaving only a small number of low scores to form the left-hand tail.

WJEC A-Level Psychology 601-5719-7

Psychology Past to Present — The Five Approaches

Topic overview The Biological Approach: assumptions of the approach and applying the assumptions to the formation of relationships The Biological Approach: love chemicals, strengths and weaknesses Biological Therapy: Drug Therapy or Psychosurgery — how the approach is used in therapy Biological Therapy: Drug Therapy or Psychosurgery — effectiveness of the therapy Classic Evidence (Biological): Raine, Buchsbaum and LaCasse (1997) — methodology and findings Classic Evidence (Biological): Raine, Buchsbaum and LaCasse (1997) — conclusions The Psychodynamic Approach: assumptions of the approach The Psychodynamic Approach: personality, defence mechanisms and the formation of relationships The Psychodynamic Approach: strengths and weaknesses of the approach Psychodynamic Therapy: Dream Analysis or Group Analysis Psychotherapy — how the approach is used Psychodynamic Therapy: Dream Analysis or Group Analysis Psychotherapy — effectiveness of the therapy Classic Evidence (Psychodynamic): Bowlby (1944) — methodology, procedures and findings Classic Evidence (Psychodynamic): Bowlby (1944) — conclusions, ethical issues and social implications The Behaviourist Approach: assumptions of the approach The Behaviourist Approach: applying the assumptions to relationships, strengths and weaknesses Behaviourist Therapy: Aversion Therapy or Systematic Desensitisation — how the approach is used Behaviourist Therapy: Aversion Therapy or Systematic Desensitisation — effectiveness of the therapy Classic Evidence (Behaviourist): Watson and Rayner (1920) — methodology, procedures and findings Classic Evidence (Behaviourist): Watson and Rayner (1920) — conclusions The Cognitive Approach: assumptions of the approach and applying the assumptions to the formation of relationships The Cognitive Approach: strengths and weaknesses of the approach Cognitive Therapy: Cognitive Behavioural Therapy or Rational Emotive Behaviour Therapy Cognitive Therapy: Cognitive Behavioural Therapy or Rational Emotive Behaviour Therapy (2)Classic Evidence (Cognitive): Loftus and Palmer (1974) — methodology, procedures and findings Classic Evidence (Cognitive): Loftus and Palmer (1974) — conclusions The Positive Approach: assumptions of the approach The Positive Approach: applying the assumptions to the formation of relationships The Positive Approach: strengths and weaknesses of the approach Positive Therapy: Mindfulness or Quality of Life Therapy — how the approach is used in therapy Positive Therapy: Mindfulness or Quality of Life Therapy — assumptions in practice, effectiveness and ethics Classic Evidence (Positive): Myers and Diener (1995) — methodology, procedures and findings Classic Evidence (Positive): Myers and Diener (1995) — conclusions Comparison of the Five Approaches: biological approach and psychodynamic approach Comparison of the Five Approaches: behaviourist approach, cognitive approach and positive approach

Contemporary Debates

Topic overview How to Explore a Contemporary Debate Debate: The Ethics of Neuroscience — what is at the core of the debate Debate: The Ethics of Neuroscience — arguments on each side of it Debate: The Mother as Primary Care-Giver of an Infant — what is at the core of the debate Debate: The Mother as Primary Care-Giver of an Infant — arguments on each side of it Debate: Using Conditioning Techniques to Control the Behaviour of Children Debate: Using Conditioning Techniques to Control the Behaviour of Children — arguments on each side Debate: Reliability of Eye-Witness Testimony (Including Children) — what is at the core of the debate Debate: Reliability of Eye-Witness Testimony (Including Children) — arguments on each side of it Debate: Relevance of Positive Psychology in Today's Society — what is at the core of the debate Debate: Relevance of Positive Psychology in Today's Society — arguments on each side of it

Principles of Research and Application of Research Methods

Topic overview Social Psychology Context Study: Milgram (1963) — methodology and procedures Social Psychology Context Study: Milgram (1963) — findings, ethical issues and social implications Developmental Psychology Context Study: Kohlberg (1968) — methodology, procedures and findings Developmental Psychology Context Study: Kohlberg (1968) — conclusions Deciding on a Research Question: aim of the research and null hypotheses Deciding on a Research Question: variables, operationalisation and extraneous variables Methodologies: experiments, quasi-experiments and participant observations Methodologies: non-participant observation, content analysis and interviews Methodologies: correlational studies, case studies and self-reports Location of Research: conducting research in a laboratory and in the field Location of Research: conducting research on-line Participants and Sampling: target populations, sampling frames and opportunity sampling Participants and Sampling: systematic sampling, stratified sampling and quota sampling Participants and Sampling: self-selected sampling and observational sampling techniques Experimental Design: independent groups and repeated measures Experimental Design: matched pairs Levels of Measurement: nominal data and ordinal data Levels of Measurement: interval data and ratio data Graphical Representation: bar charts and histograms Graphical Representation: scatter diagrams and choosing a display for the level of measurement Descriptive Statistics: the mean, the median and the mode Descriptive Statistics: the range, the standard deviation and choosing a measure Reliability Validity: internal validity and external validity Validity: specific validity issues and ways of dealing with issues of validity Ethics in Psychological Research: confidentiality, deception, protection from harm and risk to values Ethics in Psychological Research: valid consent, working with vulnerable individuals and ways of dealing with ethical issues Application of Research Methods to a Novel Scenario (AS): identifying the method and the variables Application of Research Methods to a Novel Scenario (AS): judging the reliability, validity and ethics

Mathematical Requirements for Psychology (Appendix A: AS Unit 2 and A2 Unit 4)

Topic overview Arithmetic and Numerical Computation: standard form and significant figures Arithmetic and Numerical Computation: estimating and checking a result Handling Data: means, medians, modes and ranges, percentages and percentage change Handling Data: reading a table of data and orders of magnitude Algebra Graphs: plotting and labelling a graph, gradients and intercepts Graphs: reading a value off a curve and choosing the right form of graph

Addictive BehavioursAddictive

Topic overview Addictive Behaviours: characteristics, biological explanations and the illusion of control Addictive Behaviours: individual differences explanations and social psychological explanations Addictive Behaviours: evaluating those explanations and evaluating those methods

Autistic Spectrum BehavioursAutistic spectrum

Topic overview Autistic Spectrum Behaviours: characteristics, biological and individual differences explanations Autistic Spectrum Behaviours: social psychological explanations and evaluating those explanations Autistic Spectrum Behaviours: methods of modifying the behaviour and evaluating those methods

Bullying BehavioursBullying

Topic overview Bullying Behaviours: characteristics, biological and individual differences explanations Bullying Behaviours: social psychological explanations, evaluation and CAPSLE Bullying Behaviours: methods of modifying the behaviour and evaluating those methods

Criminal BehavioursCriminal

Topic overview Criminal Behaviours: characteristics, biological explanations and Eysenck's theory Criminal Behaviours: intelligence, psychopathy and social psychological explanations Criminal Behaviours: methods of modifying the behaviour and evaluating those methods

SchizophreniaSchizophrenia

Topic overview Schizophrenia: characteristics of the behaviour and individual differences explanations Schizophrenia: social psychological explanations and evaluating those methods

StressStress

Topic overview Stress: characteristics of the behaviour and individual differences explanations Stress: social psychological explanations and evaluating those methods

Controversies in Psychology

Topic overview Controversy: Cultural Bias — issue, and why it is controversial Controversy: Cultural Bias — applying psychological knowledge to it Controversy: Cultural Bias — judgements and conclusions Controversy: Ethical Costs of Conducting Research — issue, and why it is controversial Controversy: Ethical Costs of Conducting Research — applying psychological knowledge to it Controversy: Ethical Costs of Conducting Research — judgements and conclusions Controversy: Non-Human Animals — issue, and why it is controversial Controversy: Non-Human Animals — applying psychological knowledge to it Controversy: Non-Human Animals — judgements and conclusions Controversy: Scientific Status — issue, and why it is controversial Controversy: Scientific Status — applying psychological knowledge to it Controversy: Scientific Status — judgements and conclusions Controversy: Sexism — issue, and why it is controversial Controversy: Sexism — applying psychological knowledge to it Controversy: Sexism — judgements and conclusions

Applied Research Methods

Topic overview Personal Investigations: Research Methods Skills — planning an investigation Personal Investigations: Research Methods Skills — carrying it out ethically and analysing the data Additional Methodologies (Unit 4): brain scans Additional Methodologies (Unit 4): longitudinal studies and cross-sectional studies Assessing Reliability: inter-rater reliability and test-retest reliability Assessing Reliability: split-half reliability Assessing Validity: predictive validity, face validity and content validity Assessing Validity: concurrent validity and construct validity Graphical Representation: Distribution Curves — normal distribution and its properties Graphical Representation: Distribution Curves — what a distribution shows about a data set Inferential Statistics: choosing a statistical test, parametric and non-parametric tests Inferential Statistics: calculating test values and choosing a significance level Application of Research Methods to Novel Scenarios (A2): identifying the method and the variables Application of Research Methods to Novel Scenarios (A2): judging the reliability, validity and ethics

Applied Research Methods

Graphical Representation: Distribution Curves — what a distribution shows about a data set

1 thing to know
A2 Unit 4

Overview

Ten recall questions on graphical Representation: Distribution Curves — what a distribution shows about a data set.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

In a positive skew, how do the mean, the median and the mode compare?

Questions from this subtopic

Each one with the model answer underneath.

1
Describe a positively skewed distribution.
Model answer
Most of the scores bunch up at the low end of the scale and a long tail stretches away towards the high values on the right.
2
In a positive skew, how do the mean, the median and the mode compare?
Model answer
The mode is the lowest of the three, the median lies between them, and the mean is the highest because it is dragged upwards by the extreme scores in the right-hand tail.
3
A class sits a test that almost everyone finds far too hard. What shape will the distribution of marks take?
Model answer
It will be positively skewed, because the great majority of marks cluster near the bottom of the scale with only a few higher marks trailing off to the right.
4
Describe a negatively skewed distribution.
Model answer
Most of the scores bunch up at the high end of the scale and a long tail stretches away towards the low values on the left.
5
In a negative skew, how do the mean, the median and the mode compare?
Model answer
The mean is the lowest of the three because it is pulled down by the few very low scores, the median lies between them, and the mode is the highest.
6
An easy test produces a ceiling effect. Which skew results, and why?
Model answer
A negative skew results, because nearly everyone scores at or close to the maximum, leaving only a small number of low scores to form the left-hand tail.

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Psychology Past to Present — The Five Approaches

Contemporary Debates

Principles of Research and Application of Research Methods

Mathematical Requirements for Psychology (Appendix A: AS Unit 2 and A2 Unit 4)

Cram a whole paper in one sitting

Sort every topic into what you know and what you do not, then drill only the weak ones.

Memory is .

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Rapid timed gap-fills on the terms and numbers you need to recall without thinking.

AParticipants volunteer and are already motivated.

BSamples are self-selecting.

CNo convincing placebo version exists.

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An MRI scan images structure only.

TrueFalse

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