Stats from passmed

Question 1

5 phases of clinical trial

Answer 1

0 = exploratory studies
1 = safety assessment = healthy volunteers
2 = assess efficacy = small no. pt affected by disease
3 = assess effectiveness = 100-1000s = rct = compare new and established
4 = post marketing surveillance = effective and se

Question 2

confidence interval definition

Answer 2

• range of values within which the true effect of intervention is likely to lie
• e.g. 95% = CI should contain the true effect of the intervention 95% of the time

Question 3

4 phases of drug development

Answer 3

1 = small studies on healthy = assess dynamic and kinetic
2 = small on pt = efficacy and adverse
3 = larger = efficacy and effects = comapres
4 = post marketing surveillance

Question 4

incidence is

Answer 4

no. new cases per population in given time period

Question 5

prevalence is

Answer 5

total number of cases per population at a particular point in time

Question 6

Odds ratio

Answer 6

a/c : b/d

Question 7

sensitivity

Answer 7

true positive / true positive + false negative
proportion with condition and +ve result

Question 8

specificity

Answer 8

TN/TN + FP
proportion without the condition with a -ve result

Question 9

PPV

Answer 9

TP/TP+FP
chance pt has condition if test is positive

Question 10

NPV

Answer 10

TN/TN+FN
chance doesnt have condition if test -ve

Question 11

RCT

Answer 11

random allocation to intervention or control

Question 12

cohort

Answer 12

observational and prospective
- selected according to exposure and followed up to see how many develop outcome

Question 13

case control

Answer 13

observational and retrospective
- pt with condition identified and matched with controls
- data collected on past exposure
- cheap and good for rare
- confoudning