PREVMED Pearlets

Question 1

Group of subjects who are followed forward in time to see which ones develop the outcome

Answer 1

COHORT

Question 2

Prospective studies in which an intervention is applied

Answer 2

CLINICAL TRIALS

Question 3

Similar in design to a prospective cohort study but both the exposure and outcome have occured when the study is undertaken

Answer 3

RETROSPECTIVE COHORT STUDY

Question 4

Average or sum of the observations divided by the number of observations

Answer 4

MEAN

Question 5

Middle observation in a series of ordered observations

Answer 5

MEDIAN

Question 6

Observation that occurs with greatest frequency

Answer 6

MODE

Question 7

Used for categorical data if no cell has an expected count less than 1 and no more than 20% of the cells have an expected count of less than 5

Answer 7

CHI-SQUARE

Question 8

Used when 50% of cells have an expected count less than 5

Answer 8

FISER’S EXACT TEST

Question 9

Used for independent continuous data

Answer 9

STUDENT t TEST

Question 10

Used for analysis of several independent means

Answer 10

ANALYSIS OF VARIANCE

Question 11

How are incidence rate measure

Answer 11

Number of new cases per total population x time = cases per person-years

Question 12

Ratio of incidence of a disease in a group exposed to a factor

Answer 12

RELATIVE RISK

Question 13

Investigators determine exposure of the study and control groups to a suspected causal factor and measures response in the 2 groups

Answer 13

EXPERIMENTAL STUDIES

Question 14

Type of study wherein investigators have no control over exposure to a suspected causal factor but can measure responses in those who are and are not exposed

Answer 14

OBSERVATIONAL STUDIES

Question 15

Systematic errors in the way subjects are included in the study

Answer 15

SELECTION BIAS

Question 16

Occurs when the apparent effect of an exposure is partly or entirely due to a third factor associated with both exposure and outcome

Answer 16

CONFOUNDING

Question 17

Well suited to studying rare disorders with multiple potential causes

Answer 17

CASE CONTROL STUDIES

Question 18

Window period between the time the cancer can be detected when it is asymptomatic by a screening test and the time it will become clinically apparent is short

Answer 18

LENGTH BIAS

Question 19

Occurs when the screening test advances the time of diagnosis

Answer 19

LEAD-TIME BIAS

Question 20

Systematic difference in the way data are collected for either the exposure or the outcome

Answer 20

INFORMATION BIAS