Critical numbers

Question 1

Define standard deviation

Answer 1

a measure of the average distance of the data observations from the mean value

Question 2

Define odds ratio

Answer 2

a ratio of odds in 2 groups, often used in case control studies as an approximation to estimating relative risk

Question 3

Median

Answer 3

the middle observation when data is arranged in order of increasing values. Often used to describe skewed or ordinate data

Question 4

Where is the true value likely to be?

Answer 4

Within the confidence interval

Question 5

IQR

Answer 5

represents the observation below which the bottom 25% of data lie and above which the top 25% of data lie

Question 6

p value

Answer 6

Represents the probability of observing a test statistic at least as extreme as that actually observed if the null hypothesis is true. A small p value is interpreted as strong evidence against the null hypothesis

Question 7

Mode

Answer 7

Most common value - used to describe nominal or ordinal data

Question 8

Standard error

Answer 8

For estimation - describes the precision of the mean. Tell us how far from the true value (population mean) the sample mean is

Question 9

Primary prevention

Answer 9

Prevention of disease from occurring in people who have not been diagnosed as having the disease by reducing risk factors. Includes health promotion e.g. smoking cessation reduces risk of CVD

Question 10

High risk approach to prevention

Answer 10

Targeting of health promotion to groups based on information from epidemiological studies e.g. Clamydia screening for people age 15-24

Question 11

Population approach

Answer 11

Aims to lower the level of of risk in a population, includes health promotion

Question 12

Prevention paradox

Answer 12

A prevention measure which brings much befit to the population, but may offer little to each participating individual

Question 13

Absolute risk

Answer 13

Probability / risk of an event or developing disease within a stated time period

Question 14

Relative risk

Answer 14

Probability / risk of an event or developing of a disease relative to exposure

Question 15

Tertiary prevention

Answer 15

Preventing progression of an established disease. Aims to reduce the impact of a disease (limiting disability caused by disease or preventing recurrence of events) and promotes quality of life through active rehabilitation e.g. prescribing aspirin to patients post-MI

Question 16

Ecological study

Answer 16

Observational / descriptive, uses routine data from populations, looks at prevalence, trends and correlations e.g. census or death certificates

Question 17

Cross-sectional

Answer 17

Observational / analytical; uses information from individuals to update or supply prevalence data (ONLY) Gives you a snapshot at that particular point in time

Question 18

Analytical

Answer 18

Observational (vs intervention); analytical of relationships rather than simply descriptive

Question 19

Cohort study

Answer 19

PROSPECTIVE
Observe a large number of people without a disease over a long period then compare incidence between groups that differ in terms of exposure

EXAMPLE: determine who smokes in the particular population and observe how many of the smoking cohort go on to develop lung cancer and how many non-smokers do

Question 20

Longitudinal

Answer 20

Observational study of persons over a period of time taking measurements at more than one time point

Question 21

Association

Answer 21

Existence of a relationship between variables

Question 22

Case-control

Answer 22

RETROSPECTIVE Observational study identifying persons with the disease of interest and comparing them with a suitable control group (without disease)

EXAMPLE: comparing a group of people with lung cancer to those without lung cancer and seeing how many of the people in each group smoked

Question 23

Retrospective

Answer 23

Analysis of events that occurred before the onset of disease

Question 24

Epidemiology

Answer 24

the study of frequency, distribution and determinants of disease within a population, in order to prevent / control disease

Question 25

Incidence

Answer 25

the number of new cases of a disease within a defined population over a defined time period

Question 26

Prevalence

Answer 26

the number of existing cases of a disease within a defined population at a specific point in time

Question 27

Intervention study

Answer 27

RCTs!!!!!!!!!
An intervention is given and the effects of that intervention are observed

EXAMPLE:
giving warfarin to one group of people with atrial fibrillation, and a placebo to a control group with the same disease and observe the effects

Question 28

Secondary prevention

Answer 28

Identifying disease early before symptoms are experienced, preventing progression of the disease and hopefully preventing symptoms from occurring e.g. screening programmes