Find the mode of these scores: 3, 5, 8, 5, 6, 9, 5, 2.

The mode is 5, because 5 appears three times and no other score appears more than once.

Calculate the range of these scores: 14, 8, 22, 27, 11, 19.

The range is 19. The highest score minus the lowest score is 27 − 8 = 19.

What does the range show, and why can it be misleading?

The range shows how spread out the scores are, as a measure of dispersion. A single extreme score can make the spread look much larger than it really is.

Reaction scores are 5, 6, 6, 7 and 40. Why is the median a better average than the mean here?

The extreme score of 40 pulls the mean up to 12.8, which is typical of nobody. The median of 6 is unaffected by the extreme score.

Edexcel GCSE Psychology 1PS0

Development

Topic overview Early brain development Piaget's theory of cognitive development Dweck's mindset theory and Willingham's learning theory The three mountains task and Gunderson's praise study The development of morality

Memory

Topic overview Information processing, duration and capacity Retrograde and anterograde amnesia Bartlett's theory of reconstructive memory The multi-store model, reductionism and holism War of the Ghosts and the Peterson and Peterson study

Psychological Problems

Topic overview Symptoms of depression and addiction Incidence and effects of mental health problems Explaining depression Explaining addiction Treating depression and addiction Key studies and the nature–nurture debate

The Brain and Neuropsychology

Topic overview Lobes of the brain and the effects of damage Lateralisation and Sperry's split-brain study Neurons, synapses and the central nervous system Phineas Gage and how brain research has changed

Social Influence

Topic overview Conformity to majority influence Obedience to authority Bystander intervention Crowd behaviour, society and culture Piliavin's subway study and the Stanford prison study

Criminal PsychologyOptional topic

Topic overview Operant conditioning and social learning explanations of crime Eysenck's criminal personality theory Punishment, recidivism and rehabilitation Bandura's Bobo doll study and Charlton's St Helena study

The SelfOptional topic

Topic overview Self-concept and influences on self-esteem Erikson's identity stages and belief in free will Rogers' and Maslow's humanistic theory Measuring personality and trait theory Vohs and Schooler's cheating study and Van Houtte and Jarvis's pet study

PerceptionOptional topic

Topic overview Depth cues, visual illusions and constancies Gibson's direct theory and Gregory's constructivist theory Perceptual set The Haber and Levin and Carmichael studies

Sleep and DreamingOptional topic

Topic overview Sleep stages and the sleep cycle Influences on sleep and sleep disorders Freud's theory of dreaming and activation synthesis theory Freud's Little Hans and Siffre's cave study

Language, Thought and CommunicationOptional topic

Topic overview Piaget and Vygotsky on language and thought Linguistic relativism and determinism Human and animal communication Non-verbal communication and Darwin's evolutionary theory The Yuki and Boroditsky studies

Research Methods

Topic overview Variables, hypotheses and controls Sampling methods Experiments and experimental designs Interviews, questionnaires and types of data Correlations, case studies and observations Ethical issues in psychological research Evaluating studies and the core areas of psychology Averages, calculations and graphs

Research Methods

Averages, calculations and graphs

3 things to know
Papers 1 and 2

Overview

The mean, median, mode and range, ratios, fractions, percentage change, standard form, significant figures, estimation, the normal distribution, frequency tables, bar charts and histograms.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

Find the median of these scores: 11, 4, 18, 9, 15, 7.

Key term

A group of 49 participants scored a total of 1,012 points. Estimate the mean score without a calculator.

Numbers

Calculate the mean of these scores: 12, 15, 9, 14, 10.

Questions from this subtopic

Each one with the model answer underneath.

1
Calculate the mean of these scores: 12, 15, 9, 14, 10.
Model answer
The mean is 12. The scores add up to 60, and 60 ÷ 5 = 12.
2
Find the median of these scores: 11, 4, 18, 9, 15, 7.
Model answer
The median is 10. In order the scores are 4, 7, 9, 11, 15 and 18. The middle two scores give (9 + 11) ÷ 2 = 10.
3
Find the mode of these scores: 3, 5, 8, 5, 6, 9, 5, 2.
Model answer
The mode is 5, because 5 appears three times and no other score appears more than once.
4
Calculate the range of these scores: 14, 8, 22, 27, 11, 19.
Model answer
The range is 19. The highest score minus the lowest score is 27 − 8 = 19.
5
What does the range show, and why can it be misleading?
Model answer
The range shows how spread out the scores are, as a measure of dispersion. A single extreme score can make the spread look much larger than it really is.
6
Reaction scores are 5, 6, 6, 7 and 40. Why is the median a better average than the mean here?
Model answer
The extreme score of 40 pulls the mean up to 12.8, which is typical of nobody. The median of 6 is unaffected by the extreme score.

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Development

Memory

Psychological Problems

The Brain and Neuropsychology

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Long-term memory can last for a .

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AThe median is 10.

BIn order the scores are 4, 7, 9, 11, 15 and 18.

CThe middle two scores give (9 + 11) ÷ 2 = 10.

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Short-term memory can hold about 7 ± 2 items at once.

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