2 - Stats + Data Interpretation

Question 1

levels of evidence?

Answer 1

Ia - meta analysis of RCT
b - RCT

IIa - controlled trial
b - experimental trial

III - case/comparative studies

IV - panel of experts

Question 2

best test for intervention?

Answer 2

RCT
e.g new drug

Question 3

best test for a prognosis or diagnostic test?

Answer 3

cohort study
cross sectional study

Question 4

how common is ovarian cancer?

Answer 4

22 per 100,000

Question 5

equation for likelihood ratio?

Answer 5

LR +ve = Sensitivity/ (1-Specificty)

LR -ve = (1-Sensitivity) / Specificity

Question 6

calculation for 95% confidence interval?

Answer 6

Calculation of 95% CI for mean = (mean - 1.96xSEM) to (mean +1.96xSEM)

Upper CI limit = mean + (1.96 x SEM)

Lower CI limit = mean - (1.96 x SEM)

Question 7

% success with a VBAC?

Answer 7

75%

Question 8

table?

Answer 8

Question 9

equation for sensitivity?

Answer 9

A/ A+C

Question 10

equation for specificity

Answer 10

D / B+D

Question 11

equation for PPV?

Answer 11

A/A+B

Question 12

equation for NPV?

Answer 12

D/C+D

Question 13

equation for LR?

Answer 13

LR+ = Sensitivity / (1 - Specificity)
LR- = (1- Sensitivity) / Specificity

Question 14

roc curve axis?

Answer 14

Sensitivity against 1-Specificty

Question 15

calculation for SEM?

Answer 15

Standard Error of the Mean = Standard Deviation / square root of sample size

SEM = SD/ square root of n

N = sample number

Question 16

how to calculate relative risk?

Answer 16

prevalance in exposed group / prevalance in control group

Question 17

e.g parametric tests?

Answer 17

Pearson
t/f/z test
Analaysis of variance

Question 18

e.g non parametric tests?

Answer 18

Spearman
Mann whitney
Chi
Wilcoxon signed rank

data not normally distributed in a population

Question 19

% cases of vulval cancer are squamous?

Answer 19

90%

Question 20

rate of uterine scar rupture?

Answer 20

2 in 1000

Question 21

The ability of a screening test to identify unaffected individuals is?

Answer 21

specificity

Question 22

What is the chance of her being diagnosed with cervical cancer with a smear showing low grade abnormality + HPV +ve?

Answer 22

1 in 1000

Question 23

What is the approximate chance of a pregnant woman in the UK experiencing a stillbirth?

Answer 23

1 in 200

Question 24

What is the most common gynaecological cancer in the UK?

Answer 24

endometrial

Question 25

features of mucinous cyst adenoma on US?

Answer 25

large multilocular thin walled varying degrees of echogenicity

Question 26

features of serous cyst adenoma on US?

Answer 26

unilocular

Question 27

normal range for cord gases?

Answer 27

pH 7.26 - 7.30

Question 28

what amount of fluid makes up body weight?

Answer 28

40% ICF 20% ECF 4% plasma

Question 29

cations in ECF vs ICF?

Answer 29

ECF - Na, Cl ICF - K, PO4

Question 30

how dilated should cervix be for an FBS?

Answer 30

>3cm

Question 31

what progesterone level suggests anovulation?

Answer 31

<16

Question 31

what blood test is for ovulation? when should it be taken?

Answer 31

mid-luteal progesterone sample 7 days before period

Question 32

what ecg section does the JVP a wave correspond to? significance?

Answer 32

P waves absent in AF

Question 33

US frequency used?

Answer 33

abdo - 3-3.5 TVUS - 5-7.5

Question 34

Features of functional ovarian cysts on ultrasound?

Answer 34

thin walled unilocular >3cm anechoic

Question 35

normal FHR on CTG?

Answer 35

110-160bpm

Question 36

normal variability on CTG? when is it concerning?

Answer 36

5-25bpm <5bpm for 30 mins >25bpm for 15-25mins

Question 37

what is a deceleration?

Answer 37

drop in FHR of >15 beats per minute (bpm) below the baseline, lasting 15 seconds or more

Question 38

what are B rules on US for ovarian cysts?

Answer 38

unilocular solid components <7mm acoustic shadowing smooth <100mm no blood flow

Question 39

what are M rules on US for ovarian cysts?

Answer 39

irregular ascited ≥4 papillary structures irregular with >100mm strong blood flow

Question 40

what do anti HBs and anti HBc mean?

Answer 40

anti HBs - immunity anti HBc - past infection

Question 41

normal qualitty of sperm?

Answer 41

volume 1.5ml pH >7.2 concentration 15 mil sperm number 39 mil motility 40% vitality 58% morphology 4%

Question 42

features of endometriomas on US?

Answer 42

ground glass echoes haemorrhagic

Question 43

what are US frequencies?

Answer 43

>20kHz

Question 44

what to do if FBS >7.25?

Answer 44

repeat in 1 hour if CTG still abnormal

Question 45

what does anti HBc IgM and IgG mean?

Answer 45

IgM - acute infection IgG - previous infection

Question 46

what does anti HBe mean?

Answer 46

high viral titre if high

Question 47

what are amber flags for a non reassuring CTG?

Answer 47

B - 100-109 or 161-180bpm V - <5bpm for 30-50min or >25bpm for 15-25min D - variable decels

Question 48

what are red flags for CTG?

Answer 48

B - <100 or >180bpm V - <5bpm for >50min or >25bpm for >25min D - late decels, >3min with concerning features >5 contractions in 10 mins

Question 49

normal endometrial thickness postmenopausal?

Answer 49

<4mm

Question 50

what is a normal BhCG rise?

Answer 50

>66% in 48hrs

Question 51

what is recall if smear HPV +ve?

Answer 51

normal cytology - smear in 1 yr if neg after that -> 3yrly if positive 3 times in total and cytology normal -> colp anyway

Question 52

when is re scan for low lying placenta?

Answer 52

32-34 weeks

Question 53

what is Pves Pabd Pdet on urodynamics?

Answer 53

Pves - intravesical pressure Pabd - intra abdominal Pdet - detrusor

Question 54

what would indicate stress incontinence on urodynamics?

Answer 54

change in Pves and Pabd

Question 55

what would indicate destrusor overactivity on urodynamics?

Answer 55

Pves and Pdet (not Pabd)

Question 56

rate of placenta accreta?

Answer 56

1.7 per 10,000

Question 57

what % of babies have permanent neuro dysfunction after shoulder dystocia?

Answer 57

<10%

Question 58

what % of pregnancies are affected by N+V?

Answer 58

70%

Question 59

what % of patients ROM will go into labour within 24 hrs?

Answer 59

60%

Question 60

what is power?

Answer 60

power = 1- beta (false negative rate)

Question 61

what is p value?

Answer 61

false positive rate

Question 62

perinatal mortality rate?

Answer 62

stillbirths and deaths in first week of life per 100,000 birthds

Question 63

maternal mortality rate?

Answer 63

direct and indirect deaths per 100,000 maternities

Question 64

what is a type 1 error? type II?

Answer 64

null hypothesis wrongly rejected (false +ve) acceptance of nill hypothesis is type II

Question 65

how to calculate SD?

Answer 65

SD = square root of variance