References only, not question text. Open Official paper ↗ where Cambridge publishes the paper,
or see the official Cambridge past-papers page; for other papers, ask your
school. “Paper 42” means Paper 4, variant 2.
Practice questions
Original questions written by HomiLabs in the style of the exam, with answers and mark schemes. They are not
Cambridge past paper questions and have not been reviewed by Cambridge. Try each one before opening the answer.
Q1Health promotion · Core · Paper 3 style · 4 marks
(a)Outline what is meant by 'unrealistic optimism' in health psychology.[2]
(b)Explain one way unrealistic optimism could make a health promotion campaign about road safety less effective.[2]
Show answer
(a) A belief that you are less likely than other people to experience negative health events (and more likely to experience positive ones), so you may ignore health warnings.
1 mark: less likely than others; 1 mark: effect on health behaviour.
(b) Young drivers may accept that speeding causes accidents but believe 'it won't happen to me' because they think they are better drivers than average, so they do not change their behaviour.
1 mark: 'not me' thinking; 1 mark: applied to the campaign.
Q2Health promotion · Standard · Paper 3 style · 4 marks
(a)Dr Farah runs a dental clinic in Multan and wants to persuade teenagers to stop chewing gutka. Using psychological research on fear appeals, suggest how she could design her health promotion message.[4]
Show answer
(a) Use a low-to-moderate level of fear rather than very frightening images, because research on fear arousal (Janis and Feshbach) found the minimal-fear message produced the most change in dental behaviour while strong fear produced least (people may avoid or deny a very frightening message). Combine the warning with clear, specific, achievable advice (e.g. where to get help to quit, what to chew instead), so teenagers feel able to act.
1 mark: moderate/low fear; 1 mark: research evidence; 1 mark: give clear specific actions; 1 mark: explanation (defensive avoidance / self-efficacy) applied to Dr Farah's clinic.
Q3Health promotion · Standard · Paper 3 style · 6 marks
(a)Describe the study by Janis and Feshbach on fear arousal in health promotion.[6]
Show answer
(a) Aim: to see whether the amount of fear in a health message affects behaviour change. High-school students were randomly given one of three versions of a 15-minute illustrated lecture on dental hygiene: strong fear (vivid images and warnings of pain, infection and decay), moderate fear, or minimal fear; a control group heard a lecture on a different topic. Dental hygiene practices were measured by questionnaire before and one week after. The minimal-fear group showed the greatest change towards the recommended practices and the strong-fear group the least. Conclusion: too much fear may make people avoid or dismiss the message.
1 mark each for up to 6 points: aim; sample (high-school students in the USA); three fear levels; control group; self-report questionnaire before and after; result (minimal most change, strong least); conclusion.
Q4Health promotion · Standard · Paper 3 style · 4 marks
(a)Outline the determinism versus free will debate.[2]
(b)Explain one reason why using a token economy to improve worksite safety (Fox et al.) is deterministic.[2]
Show answer
(a) Determinism is the view that behaviour is caused by forces outside our control (e.g. reinforcement, biology); free will is the view that people choose their own behaviour.
1 mark each side.
(b) It assumes miners' safe behaviour is controlled by rewards: giving trading stamps for accident-free periods reinforced safety, so behaviour is seen as shaped by consequences rather than chosen freely.
1 mark: behaviour caused by reinforcement; 1 mark: link to Fox et al. (stamps / mines / fewer days lost).
Q5Health promotion · Challenge · Paper 3 style · 10 marks
(a)Evaluate the 'Food Dudes' health promotion programme (Tapper et al.) for increasing children's fruit and vegetable consumption, including a discussion about generalisability.[10]
Show answer
(a) Strengths: high ecological validity – carried out in real schools during normal lunchtimes; objective measures of food eaten (weighing what is left) give reliable quantitative data; clear practical application – combines modelling by admired peers (the Food Dudes videos) with rewards, using social learning and operant principles; effects were maintained at follow-up. Weaknesses / issues: generalisability – UK primary schools may not represent other cultures or older children, and food preferences and school meal systems differ (e.g. in Pakistan); rewards may produce extrinsic motivation that fades once rewards stop; ethical issues are minor but involve children; difficult to separate the effect of the videos from the rewards.
Level 4 (9–10): balanced evaluation with at least four developed points, generalisability discussed in depth, linked to Food Dudes throughout. Level 3 (6–8): mostly developed points, generalisability included. Level 2 (3–5): basic points, little elaboration. Level 1 (1–2): vague or descriptive. Max 6 without generalisability.
Q6Health promotion · Challenge · Paper 4 style · 24 marks
(a)Plan a field experiment to investigate whether a health promotion programme increases handwashing before lunch in primary schools in Lahore. Your plan must include a named sampling technique and a way of measuring handwashing.[10]
(b)Describe the psychological knowledge on which your plan is based.[8]
(c)Explain one reason for your choice of sampling technique.[6]
Show answer
(a) Example: IV – schools receiving a 4-week programme (cartoon video of child 'hygiene heroes', posters and sticker rewards for washing) vs schools continuing as normal. DV – percentage of pupils who wash hands with soap before lunch, recorded by trained observers using a checklist (washes with soap for at least 20 seconds), plus soap used (grams) per week. Sample: stratified sample of 8 government and private schools, randomly assigned to conditions; pupils aged 7–9. Procedure: baseline observation for a week, programme, observation immediately after and 3 months later. Controls: same observation times, observers blind to condition. Ethics: permission from head teachers and parents, children's assent, anonymity. Data: compare mean percentages; bar chart.
Level 4 (9–10): clear, detailed, replicable plan with IV/DV, named and justified sampling technique, operationalised measure, procedure, controls and ethics. Level 3 (6–8): most features with some detail. Level 2 (3–5): basic plan. Level 1 (1–2): little relevant content.
(b) Health promotion strategies: modelling (social learning) as in the Food Dudes programme, where children copied admired peer models and received small rewards, increasing fruit and vegetable consumption; positive reinforcement and token economies (Fox et al.) increasing safe behaviour; fear appeals (Janis and Feshbach) showing that strong fear is not the most effective, so a positive, low-fear message is used; health promotion in schools reaching many children at an age when habits form.
Level 4 (7–8): accurate, detailed description of relevant theory/studies clearly linked to the plan. Level 3 (5–6): accurate with some detail. Level 2 (3–4): limited. Level 1 (1–2): vague.
(c) Stratified sampling ensures both government and private schools are represented in proportion, because hygiene facilities (soap, water) and family background differ between them; this increases generalisability to Lahore's schools. It also reduces bias compared with an opportunity sample of schools that volunteer, which may already be more health-conscious. Weakness acknowledged: it needs a full list of schools and takes time.
Level 3 (5–6): reason well explained, linked to the plan and to the psychology, with evaluation. Level 2 (3–4): reason explained with some link. Level 1 (1–2): reason stated.
Q7Health promotion · Challenge · Paper 3 style · 10 marks
(a)Evaluate health promotion in worksites and communities, including a discussion about individual and situational explanations.[10]
Show answer
(a) Strengths: worksite token economies (Fox et al.) produced large, lasting reductions in days lost through accidents – real-world, objective data, high ecological validity; community campaigns reach many people and can change norms. Issues: situational – these programmes assume behaviour can be changed by altering the environment (rewards, information, social norms), which ignores individual differences such as unrealistic optimism, personality or motivation, so some people will not respond; individual approaches (e.g. tailored advice) may be needed alongside. Other weaknesses: extrinsic rewards may stop working when removed; difficult to control extraneous variables in field settings, so cause and effect is uncertain; cultural generalisability.
Level 4 (9–10): balanced, at least four developed points, individual/situational debate discussed thoroughly with examples. Level 3 (6–8). Level 2 (3–5). Level 1 (1–2). Max 6 without the debate.
Q8Stress · Core · Paper 3 style · 6 marks
(a)Describe the General Adaptation Syndrome (Selye).[6]
Show answer
(a) Selye proposed that the body responds to any prolonged stressor in the same three stages. Alarm reaction: the stressor is detected, the sympathetic nervous system and adrenal glands release adrenaline, heart rate and blood pressure rise – 'fight or flight'. Resistance: if the stressor continues, the body adapts, with stress hormones such as cortisol staying high; the person seems to cope but resources are being used up. Exhaustion: after long-term stress, the body's resources are depleted, the immune system is weakened and stress-related illnesses (e.g. ulcers, high blood pressure) can develop. Based on experiments in which rats were exposed to different stressors.
1 mark each for up to 6 points: same response to all stressors; alarm stage with detail; resistance stage with detail; exhaustion stage with detail; link to illness/immune suppression; based on animal research.
Q9Stress · Standard · Paper 3 style · 4 marks
(a)Bilal is a bank manager in Karachi. He has frequent headaches, sleeps badly and feels tense all day. Suggest how stress inoculation training could be used to help him.[4]
Show answer
(a) Phase 1 (conceptualisation): a therapist helps Bilal identify his stressors (e.g. targets, difficult customers) and how he thinks about them. Phase 2 (skills acquisition and rehearsal): he learns coping skills such as relaxation, positive self-statements and time management and practises them in role-plays. Phase 3 (application and follow-through): he uses the skills in real situations at the bank, starting with milder stressors, with booster sessions.
1 mark per phase correctly applied (max 3); 1 mark for clear application to Bilal throughout.
Q10Stress · Standard · Paper 4 style · 4 marks
Usman, a university student in Peshawar, completes the Social Readjustment Rating Scale. In the past year he experienced: death of a close family member (63), change in living conditions (25), begin or end school (26), change in residence (20), change in sleeping habits (16) and a vacation (13). Holmes and Rahe suggested that 150–299 LCU indicates moderate risk of stress-related illness, and 300 or more indicates high risk.
(a)Calculate Usman's total life change units (LCU).[1]
(b)Using the guideline given, state Usman's level of risk.[1]
(c)Explain one weakness of using the Social Readjustment Rating Scale to measure Usman's stress.[2]
Show answer
(a) 163
63 + 25 + 26 + 20 + 16 + 13 = 163.
(b) Moderate risk (150–299).
1 mark.
(c) Each event is given a fixed value, but the same event affects people differently (e.g. moving house may be exciting for Usman, not stressful), so the score may not validly measure his stress; it also ignores daily hassles.
1 mark weakness; 1 mark explanation applied to Usman.
Q11Stress · Standard · Paper 4 style · 6 marks
(a)Explain one strength and one weakness of measuring stress using physiological measures such as heart rate or cortisol in saliva.[4]
(b)Suggest one self-report measure that could be used alongside it.[2]
Show answer
(a) Strength: objective and quantitative – the reading cannot be faked or affected by social desirability, so it is reliable and easy to compare. Weakness: physiological arousal can be caused by things other than stress (e.g. caffeine, exercise, excitement), and the equipment/setting may itself cause anxiety, so the measure may lack validity.
2 marks each: point + explanation.
(b) A daily hassles diary/scale on which participants tick which minor everyday stressors (e.g. traffic, losing things) they experienced and rate how severe each was.
1 mark named/clear measure; 1 mark detail.
Q12Stress · Standard · Paper 3 style · 4 marks
(a)Outline the nomothetic versus idiographic debate.[2]
(b)Explain one reason why the study of work stress in civil servants (Chandola et al.) is nomothetic.[2]
Show answer
(a) The nomothetic approach studies large groups to find general laws that apply to everyone; the idiographic approach studies individuals in depth to understand their unique experience.
1 mark each.
(b) It used a very large sample of London civil servants and statistical analysis to find a general relationship between work stress and coronary heart disease, rather than studying any one person's experience in depth.
1 mark large sample/general law; 1 mark link to the study.
Q13Stress · Challenge · Paper 3 style · 4 marks
(a)Explain why daily hassles may be a better predictor of psychological health than major life events, referring to research by Kanner et al.[4]
Show answer
(a) Kanner et al. found that scores on a hassles scale (minor everyday irritations such as misplacing things, traffic, concerns about weight) were a better predictor of psychological symptoms than life-events scores. Hassles happen often and accumulate, so they produce continuous low-level stress; major life events are rare and their effect may operate partly through the hassles they create (e.g. divorce leads to cooking, money worries). Uplifts may also buffer the effect of hassles.
1 mark Kanner finding; 1 mark frequency/accumulation; 1 mark life events act via hassles; 1 mark further point (uplifts / individual appraisal).
Q14Stress · Challenge · Paper 4 style · 6 marks
Ms Mehwish, a teacher in Hyderabad, has tension headaches caused by stress.
(a)Explain how biofeedback could be used to help Ms Mehwish manage her tension headaches.[4]
(b)Explain one weakness of biofeedback compared with stress inoculation training.[2]
Show answer
(a) Electrodes on her forehead measure muscle tension (EMG) and turn it into a tone or a display; she learns relaxation techniques and watches/hears the signal fall as she relaxes the muscles; the feedback rewards successful relaxation (operant conditioning); with practice she can relax without the machine and use the skill at work when she feels tension starting.
1 mark each: physiological measure; feedback signal; learning to control it by relaxation/reinforcement; transfer to everyday life.
(b) Biofeedback deals only with the physical symptoms and does not address the thoughts or situations causing her stress, so the headaches may return; SIT also teaches cognitive coping skills.
1 mark weakness; 1 mark comparison.
Q15Pain · Core · Paper 3 style · 4 marks
(a)Outline the difference between acute pain and chronic pain.[2]
(b)Explain one reason why chronic pain may need psychological as well as medical treatment.[2]
Show answer
(a) Acute pain is short-term (usually less than about 3 months) and linked to a specific injury that heals; chronic pain lasts longer than about 3 months and may continue after the tissue has healed.
1 mark each.
(b) Chronic pain is often linked to anxiety, depression and changed behaviour (e.g. avoiding activity), which can make the pain feel worse; psychological methods such as CBT address these thoughts and behaviours where painkillers alone do not.
1 mark psychological factors; 1 mark how treatment helps.
Q16Pain · Standard · Paper 3 style · 6 marks
(a)Describe the gate control theory of pain (Melzack and Wall).[6]
Show answer
(a) Pain is not simply a direct signal from injury to brain. A 'gate' in the spinal cord (dorsal horn, substantia gelatinosa) controls whether pain signals reach the brain. Small fibres (A-delta and C) carrying pain signals open the gate. Large fibres (A-beta) carrying touch/pressure, e.g. rubbing a bump, close it. Messages descending from the brain can also open or close the gate: anxiety and attention to pain open it; distraction, relaxation and positive emotion close it. This explains why the same injury causes different pain in different situations and why phantom limb pain and episodic analgesia occur.
1 mark each for up to 6 points: gate in spinal cord; small fibres open; large fibres close (example); descending control from brain; psychological factors that open/close; explains individual/situational differences or examples.
Q17Pain · Standard · Paper 3 style · 4 marks
(a)Nurse Rabia works in a children's hospital in Peshawar. Five-year-old Ali has just had an operation and cannot describe his pain in words. Suggest two ways Nurse Rabia could measure Ali's pain.[4]
Show answer
(a) 1) Paediatric self-report scale: show Ali the Wong-Baker FACES scale, six cartoon faces from 'no hurt' (0) to 'hurts worst' (10), and ask him to point to the face that shows how he feels. 2) Behavioural observation: use an observational pain scale designed for young children (e.g. the FLACC scale: face, legs, activity, cry, consolability), or a pain behaviour checklist like the UAB scale, to rate observed behaviours such as crying, guarding the wound, grimacing and reluctance to move.
2 marks each: method + application to Ali. Accept other paediatric self-report scales (e.g. a pain thermometer or colour scale) and any named or clearly described observational checklist.
Q18Pain · Standard · Paper 4 style · 6 marks
(a)Explain two strengths of the McGill Pain Questionnaire as a measure of pain.[4]
(b)Explain one weakness of the McGill Pain Questionnaire.[2]
Show answer
(a) 1) It measures the quality of pain, not just its intensity, using many descriptive words in sensory, affective and evaluative categories, so it gives a detailed picture that helps diagnosis. 2) It is standardised and produces scores (pain rating index), so pain can be compared over time or between patients, giving reliable quantitative data.
2 marks each: strength + explanation.
(b) It relies on a good vocabulary and understanding of the descriptor words, so it is unsuitable for children or people with a different first language, which could reduce validity.
1 mark weakness; 1 mark explanation.
Q19Pain · Challenge · Paper 4 style · 6 marks
In a hypothetical study, five patients with chronic back pain at a clinic in Islamabad marked their pain on a 100 mm visual analogue scale (0 = no pain, 100 = worst pain imaginable) before and after a 6-week programme of non-pain imagery and attention diversion.Before (mm): 72, 65, 80, 58, 70After (mm): 45, 50, 52, 40, 48
(a)Calculate the mean pain rating before and after the programme, in mm.[2]
(b)Calculate the percentage reduction in the mean pain rating. Give your answer to 1 decimal place.[2]
(c)Explain one reason why the researcher cannot be sure the programme caused the reduction.[2]
(c) There was no control group: pain may have reduced naturally over 6 weeks or because patients expected to improve (placebo effect / demand characteristics).
1 mark no control group; 1 mark alternative explanation.
Q20Pain · Challenge · Paper 3 style · 10 marks
(a)Evaluate psychological techniques for managing pain (such as attention diversion, non-pain imagery and cognitive redefinition), including a discussion about individual differences.[10]
Show answer
(a) Strengths: supported by gate control theory – attention and emotion close the gate; no side effects or addiction risk compared with painkillers; give patients a sense of control and can be used anywhere; useful for chronic pain alongside medical treatment. Weaknesses: individual differences – people vary in imagination, concentration and willingness to engage, and children or very anxious patients may find imagery hard, so effectiveness differs; less effective for severe acute pain; evidence often uses self-report measures, open to demand characteristics; hard to separate which component of a combined programme works.
Level 4 (9–10): balanced, four developed points, individual differences discussed thoroughly with examples. Level 3 (6–8). Level 2 (3–5). Level 1 (1–2). Max 6 without individual differences.
Q21Adherence to medical advice · Core · Paper 3 style · 4 marks
(a)Outline one subjective and one objective way of measuring adherence.[2]
(b)Explain one reason why subjective measures of adherence may lack validity.[2]
Show answer
(a) Subjective: asking patients by questionnaire or interview how often they took their medicine. Objective: counting remaining pills / electronic pill-bottle caps / blood or urine tests.
1 mark each.
(b) Patients may overstate adherence to please the doctor or avoid criticism (social desirability), or may simply forget missed doses.
1 mark reason; 1 mark explanation.
Q22Adherence to medical advice · Standard · Paper 4 style · 5 marks
Mr Javed, who lives in Lahore, is prescribed 2 tablets a day for 28 days for high blood pressure. When he returns to the clinic after 28 days, 18 tablets are left in the bottle.
(a)Calculate the number of tablets Mr Javed should have taken.[1]
(b)Calculate the percentage of prescribed tablets that Mr Javed appears to have taken. Give your answer to 1 decimal place.[2]
(c)Explain one reason why a pill count may not be a valid measure of adherence.[2]
(c) Removed tablets may not have been swallowed – a patient could throw them away or share them – or may have been taken at the wrong times, so the count can overestimate adherence.
1 mark reason; 1 mark explanation.
Q23Adherence to medical advice · Standard · Paper 3 style · 4 marks
(a)Mrs Nasreen has been prescribed tablets for high blood pressure. They make her feel tired and dizzy, and she feels perfectly well without them, so she has stopped taking them. Using the idea of rational non-adherence and the health belief model, explain her behaviour.[4]
Show answer
(a) Rational non-adherence: she has made a reasoned decision that the costs (side effects such as tiredness and dizziness) outweigh the benefits, because high blood pressure has no symptoms she can feel. Health belief model: her perceived susceptibility and severity are low (she feels well), perceived barriers (side effects) are high and perceived benefits are low, so the likelihood of taking action is low.
2 marks for rational non-adherence applied; 2 marks for HBM components applied.
Q24Adherence to medical advice · Standard · Paper 4 style · 6 marks
(a)Describe the study by Watt et al. on using a 'Funhaler' to improve adherence in children with asthma.[6]
Show answer
(a) Aim: to see whether a novel spacer device that was fun to use would improve young children's adherence to asthma medication. Sample: children aged about 1.5–6 years with asthma in Australia, and their parents. The Funhaler had a spinning toy and a whistle activated by the child's breathing. Children used their normal spacer and then the Funhaler, each for a period of about two weeks. Parents answered questions (including by telephone) about whether the child had been medicated and about problems using the device. Results: adherence was higher and parents reported fewer difficulties with the Funhaler. Conclusion: making medication fun can improve adherence in young children.
1 mark each for up to 6 accurate points: aim; sample; description of Funhaler; repeated measures design/procedure; self-report from parents; result; conclusion.
Q25Adherence to medical advice · Challenge · Paper 4 style · 6 marks
(a)Dr Kamran runs a tuberculosis (TB) clinic in Faisalabad. Patients must take antibiotics every day for six months, but many stop early. Suggest two ways of improving adherence, based on psychological research, and explain why each should work.[4]
(b)Explain one ethical issue with using rewards to improve adherence.[2]
Show answer
(a) 1) Behavioural reinforcement and reminders: send daily SMS reminders and give small rewards (e.g. travel vouchers) for attending clinic checks, because reminders and incentives have been shown to increase health behaviours such as attending immunisations (positive reinforcement). 2) Use the health belief model: explain clearly the seriousness of TB and that stopping early can cause drug-resistant TB (increase perceived severity and benefits), and reduce barriers by giving medicines for side effects or supervised dosing near home.
2 marks each: suggestion + psychological explanation.
(b) Rewards may put pressure on poorer patients so their choice is not entirely free; patients who cannot attend could feel unfairly excluded, so rewards must be fair and not coercive.
1 mark issue; 1 mark explanation.
Q26The patient-practitioner relationship · Core · Paper 3 style · 4 marks
(a)Dr Imran tells patients what is wrong and what to do without asking for their views. Dr Saba asks patients about their concerns and decides treatment together with them. Identify the style each doctor uses.[2]
(b)Outline the findings of Savage and Armstrong on patients' satisfaction with these styles.[2]
Show answer
(a) Dr Imran: doctor-centred (directive) style; Dr Saba: patient-centred (sharing) style.
1 mark each.
(b) In a study at a general practice in London, patients randomly given a directive (doctor-centred) consultation were more satisfied than patients given a sharing (patient-centred) consultation, particularly those who were ill and expected a clear diagnosis.
1 mark directive preferred / more satisfied; 1 mark detail (random allocation / questionnaire / patients wanted clear diagnosis).
Q27The patient-practitioner relationship · Standard · Paper 4 style · 6 marks
(a)Describe the study by McKinstry and Wang on doctors' dress.[6]
Show answer
(a) Aim: to find out patients' attitudes to the way doctors dress. Patients attending general practices in Scotland were shown photographs of a male and a female doctor wearing different styles of clothing, e.g. a formal suit, a white coat, smart informal dress and casual clothes such as jeans. They completed a questionnaire rating how happy they would be to see each doctor and how much confidence they would have in them. Overall, patients preferred more formal dress (suit, white coat) and casual clothes were least preferred. Older patients were especially likely to prefer formal dress. Conclusion: dress is part of a doctor's non-verbal communication and affects patients' confidence.
1 mark each for up to 6 points: aim; sample; photographs of male and female doctors; range of dress styles; rating questionnaire; results (formal preferred, older patients especially); conclusion.
Q28The patient-practitioner relationship · Standard · Paper 3 style · 4 marks
(a)Outline the individual versus situational explanations debate.[2]
(b)Using research on delay in seeking treatment (Safer et al.), explain one example of an individual explanation and one of a situational explanation.[2]
Show answer
(a) Individual explanations say behaviour is caused by personal characteristics (e.g. beliefs, personality); situational explanations say it is caused by external circumstances (e.g. cost, other people, the environment).
1 mark each.
(b) Individual: a person's own appraisal of symptoms – e.g. believing that a lump is not serious (appraisal delay), or fear of what the doctor will find. Situational: practical barriers such as cost of treatment or difficulty getting time off work, which lengthen utilisation delay.
1 mark each, linked to stages of delay.
Q29The patient-practitioner relationship · Standard · Paper 3 style · 6 marks
(a)Outline what is meant by Munchausen syndrome as a misuse of health services.[2]
(b)Explain one reason why Munchausen syndrome is usually studied using case studies.[2]
(c)Explain one problem for doctors in diagnosing Munchausen syndrome.[2]
Show answer
(a) A disorder in which a person repeatedly feigns, exaggerates or deliberately causes symptoms of illness in order to receive medical attention and treatment, often visiting many hospitals.
1 mark feigning/causing symptoms; 1 mark to gain medical attention (not money).
(b) It is rare and patients hide their behaviour, so it is not possible to gather a large sample; a case study gives detailed (idiographic) information about one patient's history over time.
1 mark rare/hidden; 1 mark depth of information.
(c) Doctors may make a type I error – diagnosing a healthy person as ill – because the feigned or self-induced symptoms appear real, leading to unnecessary tests, operations and treatments that can harm the patient.
1 mark problem; 1 mark consequence.
Q30The patient-practitioner relationship · Challenge · Paper 4 style · 6 marks
In a hypothetical screening clinic in Karachi, 200 people were checked for diabetes. Later tests showed that 40 of them really had diabetes. The clinic's doctor diagnosed 50 people as having diabetes, of whom 34 really had it. (A type I error = diagnosing a healthy person as ill; a type II error = diagnosing an ill person as healthy.)
(a)Calculate the number of type I errors made.[1]
(b)Calculate the number of type II errors made.[1]
(c)Calculate the percentage of healthy people who were wrongly diagnosed as ill.[1]
(d)Explain why practitioners might make more type I errors than type II errors.[3]
Show answer
(a) 16
50 diagnosed ill − 34 truly ill = 16 healthy people diagnosed as ill.
(b) 6
40 ill − 34 detected = 6 ill people diagnosed as healthy.
(d) Doctors usually think it is safer to diagnose a healthy person as ill than to miss a real illness, because missing an illness could have serious consequences for the patient (and for the doctor). So when unsure they tend to diagnose illness and order further tests, which increases type I errors. The cost is unnecessary anxiety, tests and treatment for healthy patients.
1 mark: missing illness seen as worse; 1 mark: so err on the side of diagnosing; 1 mark: consequence for patients.
Similar questions
Questions that test the same subtopic in different years, grouped so you can work on one skill at a time.
References only: find each question in its paper (official link where available, otherwise through your school).
