Study design

Question 1

Define quantitative data?
Define qualitative data?

Answer 1

Quantitative- measure numerical data
Qualitative- measure categorical data

Question 2

What is an example of quantative data?

Answer 2

Continuous
Discrete

Question 3

What data is age and weight?

Answer 3

Continuous

Question 4

What data is shoe size?

Answer 4

Discrete

Question 5

What are 2 types of qualitative data?

Answer 5

Nominal- not ordered e.g. ethnicity
Ordinal- ordered e.g. social class

Question 6

State 2 forms of descriptive observational studies?

Answer 6

1) Case reports- study individuals
2) Ecological study- use routinely collected data show trends
- show prevalence and association
- can’t show causation

Question 7

Explain cross sectional study? Issues?

Answer 7

Divide population into those without and those with disease
Collect data defined point in time find associations

Issues- prone bias, no time reference

Question 8

Explain case-control studies? Pros and cons?

Answer 8

Retrospective studies take ppl with disease and match ppl without disease
Match age/sex/habitat

Pro- inexpensive, quick
Cons- retrospective nature- only demonstrate association
- data might not be reliable- issues patient memory

Question 9

Explain cohort study? Adv

Answer 9

Start population without disease
Study over time see exposed to agent in question
Do they develop disease or not

Pro- low chance bias,
- absolute and relative risk can be identified
- can show causation

Question 10

Name 2 experimental/interventional studies?

Answer 10

1) RCT
2) Non-randomised control trials

Question 11

Explain RCT?

Answer 11

Patients randomised groups
One group given intervention, one group control
Outcome measured

Pros- randomisation allow confounding features equally distributed
Confounding bias minimalised
Causation

Cons- large, expensive, volounteer bias

Question 12

Explain systemic review?

Answer 12

Review of clearly formulated question
Methods critically appraise relavent research
Collect and analyse data from studies that included in review

Question 13

Explain meta analysis?

Answer 13

Statistical methods used analyse and summarise results of included studies

Question 14

Define independent variable?
Define dependent variable

Answer 14

Independent- Variable can be altered in study
Dependent- Variable dependent on independent variable/can’t altered

Question 15

State 3 criteria used to evaluate likelihood association casual?

Answer 15

Consistency
Strength association
Specificity- single cause single effect
Coherence existing theory
Altered experimention

Question 16

Define standard error?

Answer 16

Measure in confidence that the mean of sample is close to real mean

Question 17

Explain 95% confidence interval?

Answer 17

Range values within which true population parameter will lie 95% of time

Question 18

Define null hypothesis? Type 1 and type 2 error?

Answer 18

Theory been put forward to be proven incorrect- prove something else
Type 1 error- reject null hypothesis when it is true
Type 2 error- failure reject null hypothesis when it is false

Question 19

Explain P value?

Answer 19

Estimate of probability that observed diff due to chance
Usually 5%

Question 20

Define:
Ecological
Cross sectional
Cohort

Answer 20

Ecological- observational/descriptive
- use routine data from populations
- look at prevalence, trend and correlation
Cross-sectional- observational/analytical
- use information from individual
Cohort- observe large number ppl over long time period
- compare incidence between groups differ exposure

Question 21

Define association?

Answer 21

Existence of relationship between variables

Question 22

Define longitudinal?

Answer 22

Observational study of ppl over period of time- take measurement at more than one time point