Original Statistics and Epidemiology Flashcards

1
Q

How does the WHO define the perinatal mortality rate?

A

The number of stillbirths and deaths in the first week of life per 1000 live births

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2
Q

How do MBRRACE define maternal MORTALITY?

A

The number of direct and indirect deaths per 100,000 pregnancies

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3
Q

How do MBRRACE define maternal DEATH?

A

A death that occured during pregnancy or within 42 days of the end of the pregnancy

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4
Q

What is standard deviation?

A

Square root of variance

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5
Q

What is variance?

A

Standard deviation squared

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6
Q

What is the definition of sensitivity?

A

The proportion of individuals with the disease that were correctly identified by the test

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7
Q

What is the definition of specificity?

A

The proportion of individuals without the disease who were correctly identified by the test

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8
Q

What is an accurate test used for measuring distribution?

A

Kolmogorov-Smirnov

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9
Q

What is a method of estimating distribution?

A

Histogram

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10
Q

What test is used to compare means between two separate groups of PARAMETRIC data?

A

Independant student t-test

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11
Q

What test is used to compare means between two separate groups of NON-PARAMETRIC data?

A

Mann-Whitney U

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12
Q

What test is used to compare results between two paired sample of PARAMETRIC data?

A

Paired student t-test

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13
Q

What test is used to compare results between two paired sample of NON-PARAMETRIC data?

A

Wilcoxon signed rank

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14
Q

What test is used to compare three or more measurements on one subject of PARAMETRIC data?

A

Repeated ANOVA

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15
Q

What test is used to compare three or more measurements on one subject of NON-PARAMETRIC data?

A

Friedman

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16
Q

What test is used to compare one variable between three or more separate variables of PARAMETRIC data?

A

One-way ANOVA

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17
Q

What test is used to compare one variable between three or more separate variables of NON-PARAMETRIC data?

A

Kruskal Wallis

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18
Q

What test is used to look for relationships between two continuous variables of PARAMETRIC data? (i.e. correlation)

A

Pearson coefficient

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19
Q

What test is used to look for relationships between two continuous variables of NON-PARAMETRIC data? (i.e. correlation)

A

Spearman coefficient

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20
Q

What is level of evidence IV?

A

Panel of experts - weakest form of evidence

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21
Q

What is level of evidence III?

A

Evidence from case, correlation, and comparative studies

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22
Q

What is level of evidence IIb?

A

Evidence from at least one well designed experimental trial

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23
Q

What is level of evidence IIa?

A

Evidence from at least one well designed controlled trial which is not randomized

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24
Q

What is level of evidence Ib?

A

Evidence from at least one Randomized Controlled Trial

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25
Q

What is level of evidence Ia?

A

Evidence from Meta-analysis of Randomized Controlled Trials

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26
Q

How is SEM (standard error of the mean) calculated?

A

SEM = SD/square root of sample size

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27
Q

How do you calculate 95% confidence intervals using SEM?

A

(mean - 1.96SEM) to (mean + 1.96SEM)

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28
Q

What is the incidence of ovarian cancer in the UK?

A

22/100,000

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29
Q

What is the maternal mortality rate for ectopic pregnancy in the UK?

A

2/1000 (0.2%)

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30
Q

What proportion of pregnancies are ectopic?

A

11/1000

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31
Q

What is the most common type of ectopic pregnancy?

A

Tubal - accounts for 93-95%

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32
Q

What is the risk of respiratory problems in VBAC compared to ELCS?

A

2-3% compared to 3-4%

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33
Q

What are the risks of VBAC?

A

1% additional risk of blood transfusion and endometritis
2-3/10,000 additional risk of birth-related perinatal death
22-74/10,000 risk of uterine rupture
8/10,000 develop HIE

34
Q

What are the chances of success for a first VBAC?

A

72-76%

35
Q

What are the chances of success of a 2nd VBAC, following a previously successful one?

A

87-90%

36
Q

What factors reduce the likelihood of success of VBAC?

A

1) Induced labour
2) No prev. vaginal birth
3) BMI >30
4) If the C-section previously was for dystocia

37
Q

What is the 5 year survival rate of stage I ovarian cancers?

A

90%

38
Q

What is the 5 year survival rate of stage IV ovarian cancers?

A

17%

39
Q

What is the most common cause of maternal mortality?

A

Cardiac disease (indirect)

40
Q

What is the most common direct cause of maternal mortality?

A

VTE

41
Q

What is the average age of diagnosis of endometrial cancer?

A

60

42
Q

What is the absolute risk?

A

= the actual risk

43
Q

What is relative risk?

A

= the ratio of risk comparing the risk in exposed vs. controlled groups

44
Q

What are the risk factors for endometrial cancer?

A

1) PCOS
2) Obesity
3) Late menopause
4) Early menarche
5) HRT
6) Nulliparous
7) Diabetes
8) PD
9) Tamoxifen

45
Q

How is sensitivity calculated?

A

A/(A+C)

46
Q

How is specificity calculated?

A

D/(B+D)

47
Q

How is negative predictive value (NPV) calculated?

A

D/(C+D)

48
Q

How is positive predictive value (PPV) calculated?

A

A/(A+B)

49
Q

What is the negative likelihood ratio?

A

(1-sensitivity)/specifity

50
Q

What is the positive likelihood ratio?

A

sensitivity/(1-specifity)

51
Q

What factor increases the risk of ovarian cancer?

A

Oestrogen-only HRT

52
Q

What factors decrease the risk of ovarian cancer?

A

1) OCP
2) Increased parity
3) Breastfeeding
4) Hysterectomy
5) Tubal ligation
6) Statins
7) SLE

53
Q

What is the most appropriate method to assess prognosis?

A

Cohort study

54
Q

What is the miscarriage rate age 20-29?

A

10%

55
Q

What is the miscarriage rate age 30-34?

A

15%

56
Q

What is the miscarriage rate age 35-39?

A

25%

57
Q

What is the miscarriage rate age 40-44?

A

50%

58
Q

What is the miscarriage rate age >/=45?

A

90%

59
Q

What do parametric tests assume?

A

Normal distribution

60
Q

What type of tests are used when the population distribution is not known?

A

Non-parametric

61
Q

What are the parametric tests?

A

Pearson; t-test; f-test; ANOVA; z-test

62
Q

What are the non-parametric test?

A

Spearman; Mann-Whitney; Chi2; Wilcoxen signed rank; Fisher exact probability; Kruskal Wallis; Friedman

63
Q

What are type I errors?

A

Incorrect rejection of a null hypothesis
False +ve
Detecting an effect that is not present

64
Q

What are the type II errors?

A

Incorrect acceptance of a null hypothesis
False -ve
Failing to detect an effect that is present

65
Q

What are ROC curves?

A

y = sensitivity
x = 1-specificty

66
Q

What is the most appropriate method to assess diagnostic tests?

A

Cross-sectional studies

67
Q

What is the most appropriate method to assess treatment/intervention?

A

RCT

68
Q

How should the power of a study be described?

A

The study’s ability to detect an effect of a specified size?

69
Q

Which condition is associated with a ‘greek helmet’ facial profile?

A

Wolf-Hirschhorn syndrome

70
Q

What is the definition of incidence?

A

Number of new cases of a disease that occur in a population previously free of it

71
Q

What is the definition of prevalence?

A

The frequency of existing disease at a given time

72
Q

What are the parameters measured in APGAR scoring?

A

Pulse
Respiration
Muscle tone
Reflexes/irritability
Colour

73
Q

How is cystometry performed?

A

Catheter placed in bladder with a pressure transducer to measure intravesical pressure
2nd catheter placed in either vagina or rectum to measure intra-abdominal pressure

74
Q

How is detrusor pressure measured in cystometry?

A

Intravesical pressure - intra-abdominal pressure

75
Q

What is a Kaplan-Meier plot used to graphically represent?

A

Probability of survival

76
Q

What are case-control studies useful for?

A

Rare diseases

77
Q

What are different types of categorical data?

A

Nominal/binary
Ordinal

78
Q

What are different types of quantitive data?

A

Continuous
Discrete

79
Q

What is mean sensitive to?

A

Outliers (extreme values)

80
Q

The higher the power of a study, the lower the probability of what?

A

The higher the power of a study, the lower the probability of type II errors

81
Q

High sensitivity is required for which sort of tests?

A

Screening tests, thus minimising missed cases

82
Q

High specificity is required for which sort of tests?

A

Diagnostic tests, thus minimising misdiagnoses