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Question Difficulty Analysis

Questions ranked by error rate

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Total Questions
79
Causal
44
Correlation
35
Total Attempts
276
  1. #1CausalVery HardID: 20

    More frequent handwashing correlates with more skin problems.

    Frequent handwashing can damage skin, and washing with soap and water fails to effectively reduce contamination on damaged hands.

    View Source (opens in a new tab)
    Difficulty
    63.6
    Error Rate
    63.6%
    Accuracy
    36.4%
    Attempts
    11
    Avg. Confidence
    89.5%

    4 correct, 7 incorrect

  2. #2CausalHardID: 53

    Daylight saving time transition causes short-term increase in heart attacks.

    Sleep deprivation and circadian disruption acutely increase heart attack risk.

    View Source (opens in a new tab)
    Difficulty
    56.1
    Error Rate
    60.0%
    Accuracy
    40.0%
    Attempts
    10
    Avg. Confidence
    78.9%

    4 correct, 6 incorrect

  3. #3CausalHardID: 42

    People who journal are more emotionally stable.

    Web-based positive affect journaling reduced distress, depression, and anxiety while boosting well-being and resilience.

    View Source (opens in a new tab)
    Difficulty
    50.9
    Error Rate
    71.4%
    Accuracy
    28.6%
    Attempts
    7
    Avg. Confidence
    72.4%

    2 correct, 5 incorrect

  4. #4CausalHardID: 55

    Early antibiotic exposure increases risk of childhood obesity.

    Antibiotics disrupt the microbiome and affect metabolism and appetite regulation.

    View Source (opens in a new tab)
    Difficulty
    42.8
    Error Rate
    80.0%
    Accuracy
    20.0%
    Attempts
    5
    Avg. Confidence
    90.2%

    1 correct, 4 incorrect

  5. #5CausalHardID: 91

    Birth control pills reduce ovarian cancer risk by 50%.

    Ovulation suppression protects against ovarian cancer. Effect persists years after stopping.

    View Source (opens in a new tab)
    Difficulty
    42.8
    Error Rate
    80.0%
    Accuracy
    20.0%
    Attempts
    5
    Avg. Confidence
    69.2%

    1 correct, 4 incorrect

  6. #6CorrelationHardID: 2

    People with low vitamin D levels are more often depressed.

    Association present, but direction unclear: Depressed people go outside less (reverse causality). Mendelian randomization studies show little causal evidence.

    View Source (opens in a new tab)
    Difficulty
    40.7
    Error Rate
    57.1%
    Accuracy
    42.9%
    Attempts
    7
    Avg. Confidence
    78.4%

    3 correct, 4 incorrect

  7. #7CorrelationMediumID: 31

    Higher screen time causes ADHD symptoms.

    Children with ADHD use screens for stimulation (reverse causality). Self-regulation is the actual factor.

    View Source (opens in a new tab)
    Difficulty
    38.5
    Error Rate
    44.4%
    Accuracy
    55.6%
    Attempts
    9
    Avg. Confidence
    84.1%

    5 correct, 4 incorrect

  8. #8CorrelationMediumID: 19

    People who sleep more are more productive.

    People without stress sleep more and are more productive. Stress is the common factor.

    View Source (opens in a new tab)
    Difficulty
    32.7
    Error Rate
    75.0%
    Accuracy
    25.0%
    Attempts
    4
    Avg. Confidence
    98.3%

    1 correct, 3 incorrect

  9. #9CorrelationMediumID: 117

    Skipping breakfast causes weight gain.

    Studies show breakfast skippers often consume fewer calories. No clear causation.

    View Source (opens in a new tab)
    Difficulty
    22.1
    Error Rate
    100.0%
    Accuracy
    0.0%
    Attempts
    2
    Avg. Confidence
    80.5%

    0 correct, 2 incorrect

  10. #10CorrelationMediumID: 11

    Higher coffee consumption correlates with lower Alzheimer's risk.

    Healthier people drink more coffee (reverse causality). Genetic factors influence both.

    View Source (opens in a new tab)
    Difficulty
    22.1
    Error Rate
    66.7%
    Accuracy
    33.3%
    Attempts
    3
    Avg. Confidence
    92.0%

    1 correct, 2 incorrect

  11. #11CausalMediumID: 79

    Antibiotic treatment cures bacterial pneumonia.

    Antibiotics reduce mortality from bacterial pneumonia by 80-90%.

    View Source (opens in a new tab)
    Difficulty
    22.1
    Error Rate
    66.7%
    Accuracy
    33.3%
    Attempts
    3
    Avg. Confidence
    93.0%

    1 correct, 2 incorrect

  12. #12CausalMediumID: 51

    Regular aerobic exercise reduces depressive symptoms.

    RCTs show moderate to strong effects. Exercise increases neuroplasticity and neurotransmitters.

    View Source (opens in a new tab)
    Difficulty
    21.8
    Error Rate
    50.0%
    Accuracy
    50.0%
    Attempts
    4
    Avg. Confidence
    87.5%

    2 correct, 2 incorrect

  13. #13CausalMediumID: 85

    Fluoride toothpaste prevents cavities.

    Fluoride remineralizes tooth enamel. Cochrane review shows 24% cavity reduction.

    View Source (opens in a new tab)
    Difficulty
    21.8
    Error Rate
    50.0%
    Accuracy
    50.0%
    Attempts
    4
    Avg. Confidence
    82.5%

    2 correct, 2 incorrect

  14. #14CausalMediumID: 68

    Air pollution from particulate matter causes cardiovascular disease.

    Reduction of particulate matter leads to measurable improvement in heart health.

    View Source (opens in a new tab)
    Difficulty
    21.4
    Error Rate
    40.0%
    Accuracy
    60.0%
    Attempts
    5
    Avg. Confidence
    85.6%

    3 correct, 2 incorrect

  15. #15CorrelationMediumID: 5

    Schools with more school social workers have higher reported rates of bullying.

    Detection bias: More social workers lead to better detection and reporting, not more bullying.

    View Source (opens in a new tab)
    Difficulty
    20.9
    Error Rate
    33.3%
    Accuracy
    66.7%
    Attempts
    6
    Avg. Confidence
    89.3%

    4 correct, 2 incorrect

  16. #16CorrelationEasyID: 1

    In cities with high organic food purchase, school grades are better.

    Socio-economic confounder: Wealthier families buy organic more often and provide more educational resources.

    View Source (opens in a new tab)
    Difficulty
    18.7
    Error Rate
    20.0%
    Accuracy
    80.0%
    Attempts
    10
    Avg. Confidence
    90.0%

    8 correct, 2 incorrect

  17. #17CausalEasyID: 99

    Blue light screen filters do not measurably improve sleep quality.

    RCTs show no significant effects. Screen time reduction itself is more important than blue light filtering.

    View Source (opens in a new tab)
    Difficulty
    11.1
    Error Rate
    50.0%
    Accuracy
    50.0%
    Attempts
    2
    Avg. Confidence
    100.0%

    1 correct, 1 incorrect

  18. #18CausalEasyID: 81

    Noise exposure causes hearing loss.

    Dose-dependent damage to hair cells in inner ear is well documented.

    View Source (opens in a new tab)
    Difficulty
    11.1
    Error Rate
    50.0%
    Accuracy
    50.0%
    Attempts
    2
    Avg. Confidence
    90.5%

    1 correct, 1 incorrect

  19. #19CorrelationEasyID: 37

    Higher omega-3 intake leads to better heart health.

    People who consume omega-3 generally eat more fish and healthier. RCTs show weak or no effects.

    View Source (opens in a new tab)
    Difficulty
    11.1
    Error Rate
    50.0%
    Accuracy
    50.0%
    Attempts
    2
    Avg. Confidence
    78.0%

    1 correct, 1 incorrect

  20. #20CausalEasyID: 58

    Lead exposure in childhood permanently lowers IQ.

    Neurotoxic effect on developing brain is well documented.

    View Source (opens in a new tab)
    Difficulty
    11.1
    Error Rate
    50.0%
    Accuracy
    50.0%
    Attempts
    2
    Avg. Confidence
    76.0%

    1 correct, 1 incorrect

  21. #21CausalEasyID: 93

    Speed limits reduce traffic fatalities.

    Kinetic energy increases quadratically with speed. 10 km/h reduction lowers deaths by 20-30%.

    View Source (opens in a new tab)
    Difficulty
    11.1
    Error Rate
    50.0%
    Accuracy
    50.0%
    Attempts
    2
    Avg. Confidence
    100.0%

    1 correct, 1 incorrect

  22. #22CorrelationEasyID: 9

    Places with more churches have more crime.

    Larger cities have more churches and more crimes – population size is the confounder.

    View Source (opens in a new tab)
    Difficulty
    11.1
    Error Rate
    50.0%
    Accuracy
    50.0%
    Attempts
    2
    Avg. Confidence
    86.0%

    1 correct, 1 incorrect

  23. #23CorrelationEasyID: 13

    People who take more vitamins live longer.

    Health-conscious people take vitamins and have overall healthier lifestyles (confounder).

    View Source (opens in a new tab)
    Difficulty
    11.1
    Error Rate
    50.0%
    Accuracy
    50.0%
    Attempts
    2
    Avg. Confidence
    89.0%

    1 correct, 1 incorrect

  24. #24CorrelationEasyID: 17

    People who eat breakfast daily are slimmer.

    People with healthier lifestyles are more likely to eat breakfast. RCTs show: Breakfast itself doesn't cause weight loss.

    View Source (opens in a new tab)
    Difficulty
    11.1
    Error Rate
    50.0%
    Accuracy
    50.0%
    Attempts
    2
    Avg. Confidence
    92.5%

    1 correct, 1 incorrect

  25. #25CausalEasyID: 71

    Sleeping on stomach increases risk of sudden infant death syndrome.

    "Back to Sleep" campaign reduced SIDS by 50%. Clear causality through airway obstruction.

    View Source (opens in a new tab)
    Difficulty
    11.1
    Error Rate
    50.0%
    Accuracy
    50.0%
    Attempts
    2
    Avg. Confidence
    100.0%

    1 correct, 1 incorrect

  26. #26CorrelationEasyID: 122

    We only use 10% of our brain.

    Neuroscientifically debunked - the whole brain is active, though not all areas simultaneously.

    View Source (opens in a new tab)
    Difficulty
    11.1
    Error Rate
    50.0%
    Accuracy
    50.0%
    Attempts
    2
    Avg. Confidence
    57.5%

    1 correct, 1 incorrect

  27. #27CausalEasyID: 59

    Seatbelts reduce fatal car accidents.

    Physical protection mechanism with clear effect on injury severity.

    View Source (opens in a new tab)
    Difficulty
    11.0
    Error Rate
    33.3%
    Accuracy
    66.7%
    Attempts
    3
    Avg. Confidence
    96.0%

    2 correct, 1 incorrect

  28. #28CausalEasyID: 70

    Statins reduce the risk of heart attacks.

    Large RCTs show consistent 25-30% risk reduction through cholesterol lowering.

    View Source (opens in a new tab)
    Difficulty
    10.9
    Error Rate
    25.0%
    Accuracy
    75.0%
    Attempts
    4
    Avg. Confidence
    90.5%

    3 correct, 1 incorrect

  29. #29CausalEasyID: 61

    Handwashing with soap prevents infectious diseases.

    Mechanical removal of pathogens reduces transmission by 30-50%.

    View Source (opens in a new tab)
    Difficulty
    10.9
    Error Rate
    25.0%
    Accuracy
    75.0%
    Attempts
    4
    Avg. Confidence
    90.3%

    3 correct, 1 incorrect

  30. #30CausalEasyID: 67

    Obesity increases the risk of type 2 diabetes.

    Weight reduction demonstrably reduces diabetes risk. Clear biological mechanism.

    View Source (opens in a new tab)
    Difficulty
    10.9
    Error Rate
    25.0%
    Accuracy
    75.0%
    Attempts
    4
    Avg. Confidence
    89.0%

    3 correct, 1 incorrect

  31. #31CausalEasyID: 72

    HPV vaccination prevents cervical cancer.

    HPV causes 99% of cervical cancers. Vaccination reduces precancerous lesions by 90%.

    View Source (opens in a new tab)
    Difficulty
    10.9
    Error Rate
    25.0%
    Accuracy
    75.0%
    Attempts
    4
    Avg. Confidence
    97.8%

    3 correct, 1 incorrect

  32. #32CausalEasyID: 74

    Secondhand smoke causes lung cancer in non-smokers.

    Meta-analyses show 20-30% increased lung cancer risk with chronic exposure.

    View Source (opens in a new tab)
    Difficulty
    10.9
    Error Rate
    25.0%
    Accuracy
    75.0%
    Attempts
    4
    Avg. Confidence
    86.3%

    3 correct, 1 incorrect

  33. #33CausalEasyID: 77

    Trans fats increase risk of cardiovascular disease.

    Each 2% increase in trans fat consumption raises heart risk by 23%. Bans show positive effects.

    View Source (opens in a new tab)
    Difficulty
    10.8
    Error Rate
    100.0%
    Accuracy
    0.0%
    Attempts
    1
    Avg. Confidence
    100.0%

    0 correct, 1 incorrect

  34. #34CausalEasyID: 88

    Physical activity lowers colon cancer risk.

    Meta-analyses show 20-30% risk reduction. Mechanism: accelerated intestinal transit, immune modulation.

    View Source (opens in a new tab)
    Difficulty
    10.7
    Error Rate
    20.0%
    Accuracy
    80.0%
    Attempts
    5
    Avg. Confidence
    83.4%

    4 correct, 1 incorrect

  35. #35CorrelationEasyID: 7

    Countries with higher chocolate consumption have more Nobel laureates.

    Both are linked to prosperity and research capacity.

    View Source (opens in a new tab)
    Difficulty
    10.7
    Error Rate
    20.0%
    Accuracy
    80.0%
    Attempts
    5
    Avg. Confidence
    85.2%

    4 correct, 1 incorrect

  36. #36CorrelationEasyID: 4

    Places with more bicycle helmet sales have more head injuries.

    Regions with high bicycle traffic have more accidents and more helmet purchases. Helmet sales mark cycling density.

    View Source (opens in a new tab)
    Difficulty
    10.7
    Error Rate
    20.0%
    Accuracy
    80.0%
    Attempts
    5
    Avg. Confidence
    88.2%

    4 correct, 1 incorrect

  37. #37CausalEasyID: 90

    High-dose radiation therapy causes tissue damage.

    Ionizing radiation damages DNA and cells in dose-dependent manner.

    View Source (opens in a new tab)
    Difficulty
    10.4
    Error Rate
    16.7%
    Accuracy
    83.3%
    Attempts
    6
    Avg. Confidence
    96.2%

    5 correct, 1 incorrect

  38. #38CausalEasyID: 86

    Breastfeeding reduces infection risk in infants.

    Breast milk contains antibodies and reduces respiratory and GI infections by 50-70%.

    View Source (opens in a new tab)
    Difficulty
    10.4
    Error Rate
    16.7%
    Accuracy
    83.3%
    Attempts
    6
    Avg. Confidence
    86.3%

    5 correct, 1 incorrect

  39. #39CorrelationEasyID: 10

    More hospital beds mean more diseases.

    Regions with higher disease burden build more beds. Bed numbers are an indicator, not a cause.

    View Source (opens in a new tab)
    Difficulty
    10.4
    Error Rate
    16.7%
    Accuracy
    83.3%
    Attempts
    6
    Avg. Confidence
    83.2%

    5 correct, 1 incorrect

  40. #40CorrelationEasyID: 3

    The more firefighters deployed to a fire, the larger the damage.

    The severity of the fire causes both: big fires require more personnel and cause more damage.

    View Source (opens in a new tab)
    Difficulty
    9.6
    Error Rate
    11.1%
    Accuracy
    88.9%
    Attempts
    9
    Avg. Confidence
    83.7%

    8 correct, 1 incorrect

  41. #41CausalEasyID: 89

    Malaria bed nets reduce malaria deaths by 50%.

    Insecticide-treated nets prevent mosquito bites and thus transmission.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    3
    Avg. Confidence
    91.7%

    3 correct, 0 incorrect

  42. #42CausalEasyID: 92

    Vitamin A supplementation reduces child mortality in developing countries.

    Meta-analyses show 24% reduction in all-cause mortality in children.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    3
    Avg. Confidence
    100.0%

    3 correct, 0 incorrect

  43. #43CorrelationEasyID: 110

    Shoe size causes better reading ability in children.

    Age is the common factor - older children have bigger feet AND read better.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    2
    Avg. Confidence
    99.5%

    2 correct, 0 incorrect

  44. #44CausalEasyID: 83

    Sunscreen reduces skin cancer risk.

    Long-term studies show 40% reduction of melanomas with regular use.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    3
    Avg. Confidence
    93.3%

    3 correct, 0 incorrect

  45. #45CorrelationEasyID: 123

    Hair grows back thicker after shaving.

    Optical illusion - blunt ends appear thicker. Genetics determine actual hair thickness.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    100.0%

    1 correct, 0 incorrect

  46. #46CausalEasyID: 62

    High blood pressure causes strokes.

    Blood pressure reduction demonstrably reduces stroke risk by 30-40% in RCTs.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    2
    Avg. Confidence
    100.0%

    2 correct, 0 incorrect

  47. #47CorrelationEasyID: 127

    Swimming immediately after eating is dangerous.

    No increased drowning risk. At most slight stomach discomfort possible.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    100.0%

    1 correct, 0 incorrect

  48. #48CorrelationEasyID: 107

    Margarine consumption causes divorces in Maine.

    Random correlation without plausible mechanism. Classic example of data mining.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    3
    Avg. Confidence
    84.0%

    3 correct, 0 incorrect

  49. #49CausalEasyID: 96

    Anesthetic drugs cause unconsciousness.

    Dose-dependent, reversible suppression of neuronal activity is well understood.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    4
    Avg. Confidence
    88.3%

    4 correct, 0 incorrect

  50. #50CorrelationEasyID: 8

    Larger shoe sizes are associated with better reading ability.

    Age is the hidden factor: older children have bigger feet and read better.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    10
    Avg. Confidence
    85.8%

    10 correct, 0 incorrect

  51. #51CorrelationEasyID: 134

    Gluten-free diet is healthier for everyone.

    Only necessary for celiac patients. No health benefits proven for others.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    75.0%

    1 correct, 0 incorrect

  52. #52CorrelationEasyID: 143

    Exercise alone leads to significant weight loss.

    Studies show only ~6lbs loss without caloric restriction. Diet + exercise together effective.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    80.0%

    1 correct, 0 incorrect

  53. #53CorrelationEasyID: 109

    Sleeping with light on causes myopia.

    Myopic parents are more likely to leave light on AND pass on myopia. Parental myopia is the common factor.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    3
    Avg. Confidence
    80.7%

    3 correct, 0 incorrect

  54. #54CorrelationEasyID: 115

    Root canals cause cancer.

    No scientific evidence. Confusion of correlation with causation.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    100.0%

    1 correct, 0 incorrect

  55. #55CorrelationEasyID: 108

    Cheese consumption causes death by tangling in bedsheets.

    Spurious correlation - no biological or logical connection.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    100.0%

    1 correct, 0 incorrect

  56. #56CausalEasyID: 60

    Measles vaccination programs have drastically reduced mortality.

    WHO data show millions of deaths prevented by immunization.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    2
    Avg. Confidence
    100.0%

    2 correct, 0 incorrect

  57. #57CorrelationEasyID: 114

    Vitamin D deficiency causes COVID-19 deaths.

    Life expectancy is the common factor - better healthcare detects more cases and has older population.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    79.0%

    1 correct, 0 incorrect

  58. #58CorrelationEasyID: 135

    Organic foods are always more nutritious.

    Nutrient content varies but not systematically higher in organic. Reduced pesticides yes, but not more nutrients.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    72.0%

    1 correct, 0 incorrect

  59. #59CausalEasyID: 52

    Infection with Helicobacter pylori causes stomach ulcers.

    Antibiotic treatment cures ulcers. Nobel Prize 2005 for this discovery.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    6
    Avg. Confidence
    73.3%

    6 correct, 0 incorrect

  60. #60CausalEasyID: 65

    UV radiation causes skin cancer.

    DNA damage from UV radiation is causally proven for skin cancer.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    3
    Avg. Confidence
    93.0%

    3 correct, 0 incorrect

  61. #61CausalEasyID: 69

    Alcohol during pregnancy causes fetal alcohol spectrum disorders.

    Direct toxic effect on fetal development, no safe amount known.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    2
    Avg. Confidence
    94.5%

    2 correct, 0 incorrect

  62. #62CausalEasyID: 75

    Sleep deprivation measurably impairs cognitive performance.

    Experimental studies show dose-dependent deterioration of attention and memory.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    95.0%

    1 correct, 0 incorrect

  63. #63CorrelationEasyID: 6

    The more ice cream sold, the more drowning cases occur.

    Both increase in summer. The common cause is temperature/season.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    6
    Avg. Confidence
    95.3%

    6 correct, 0 incorrect

  64. #64CausalEasyID: 100

    Salt reduction lowers blood pressure.

    Meta-analyses of RCTs show 5-6 mmHg systolic blood pressure reduction with salt reduction.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    4
    Avg. Confidence
    88.3%

    4 correct, 0 incorrect

  65. #65CausalEasyID: 54

    Prenatal famine exposure increases later risk of metabolic disease.

    Epigenetic programming during critical developmental phases has lifelong consequences.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    5
    Avg. Confidence
    85.8%

    5 correct, 0 incorrect

  66. #66CorrelationEasyID: 12

    Countries with higher education spending have more suicides.

    Wealthier countries spend more on education and have better suicide reporting systems (better detection).

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    2
    Avg. Confidence
    75.5%

    2 correct, 0 incorrect

  67. #67CausalEasyID: 76

    Motorcycle helmet laws reduce fatal head injuries.

    Helmets reduce death risk by 37% and brain injuries by 69%.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    2
    Avg. Confidence
    72.5%

    2 correct, 0 incorrect

  68. #68CausalEasyID: 82

    Excessive alcohol consumption causes liver cirrhosis.

    Clear dose-response relationship, biological mechanism known, abstinence can stop progression.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    2
    Avg. Confidence
    96.5%

    2 correct, 0 incorrect

  69. #69CorrelationEasyID: 124

    Antiperspirants cause breast cancer.

    No scientific evidence for causal link despite correlation theories.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    100.0%

    1 correct, 0 incorrect

  70. #70CorrelationEasyID: 102

    Storks deliver babies.

    Classic spurious correlation example. Both correlate with village size/rural areas, not with each other.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    100.0%

    1 correct, 0 incorrect

  71. #71CorrelationEasyID: 105

    Nicolas Cage films cause swimming pool drownings.

    Pure random correlation without any causal mechanism.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    2
    Avg. Confidence
    86.0%

    2 correct, 0 incorrect

  72. #72CorrelationEasyID: 45

    People with better posture are more confident.

    Confident people have better posture. Depression and anxiety lead to worse posture (reverse causality).

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    3
    Avg. Confidence
    82.7%

    3 correct, 0 incorrect

  73. #73CausalEasyID: 56

    Water chlorination dramatically reduces diarrheal diseases.

    Killing pathogens in water directly prevents infections.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    3
    Avg. Confidence
    72.0%

    3 correct, 0 incorrect

  74. #74CausalEasyID: 78

    Chemotherapy extends survival in many cancer types.

    RCTs show significant survival benefits in numerous cancer types.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    2
    Avg. Confidence
    96.0%

    2 correct, 0 incorrect

  75. #75CausalEasyID: 98

    Stress increases blood cortisol levels.

    HPA axis activation as direct physiological stress response is well documented.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    2
    Avg. Confidence
    100.0%

    2 correct, 0 incorrect

  76. #76CausalEasyID: 57

    Smoking causes lung cancer.

    Strong dose-response relationship, biological mechanism known, multiple study designs consistent.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    100.0%

    1 correct, 0 incorrect

  77. #77CausalEasyID: 87

    Aspirin reduces stroke risk in high-risk patients.

    Platelet aggregation inhibition prevents vascular occlusion. 25% risk reduction in RCTs.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    2
    Avg. Confidence
    77.0%

    2 correct, 0 incorrect

  78. #78CorrelationEasyID: 14

    Households with more books have smarter children.

    Parents' education level influences both: book acquisition and cognitive support of children.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    76.0%

    1 correct, 0 incorrect

  79. #79CausalEasyID: 66

    Folic acid supplementation reduces neural tube defects in newborns.

    Randomized studies show 70% reduction of spina bifida and anencephaly.

    View Source (opens in a new tab)
    Difficulty
    0.0
    Error Rate
    0.0%
    Accuracy
    100.0%
    Attempts
    1
    Avg. Confidence
    81.0%

    1 correct, 0 incorrect