Topic 1: Biological Studies

Question 1

Biological studies can be carried out to investigate risk factors for CVD or to evaluate treatments.

Explain Cohort Studies (2 ways)

Answer 1

1. group of people followed over time (every 1-2 years have detailed medical + questions about lifestyle) to see who develops the disease

OR

2. compare group exposed to a risk factor with group who are not exposed and see who develops the condition

Question 2

Biological studies can be carried out to investigate risk factors for CVD or to evaluate treatments.

Explain case-control studies (1 point)

Answer 2

1. people who have disease are compared with those who do not (control group), followed over time

Question 3

How can a {hypothesis/aim} be made valid? (1 point)

Answer 3

2. the results of the experiment must allow a conclusion linked to what the study set out to investigate

Question 4

Why do we need a large sample size? (2 reasons)

Answer 4

1. makes {data/results} more RELIABLE, so therefore more VALID
2. anomalies (and side effects from drug trials) are more likely to show up

Question 5

Why do we need repeats? (2 reasons)

What kind of method is needed for it to be repeated?

Answer 5

1. Anomalies can be {identified/discarded/repeated} and a mean can be calculated
2. Range or standard deviation can be calculated – small standard deviation or range bars indicate higher reliability

Standardised method

Question 6

What is a representative sample? (1 point)

Why do we need it? (1 point)

Answer 6

1. data collected from a range of people (gender, ethnic group, different nationalities)
2. otherwise conclusions MAY NOT BE GENERALISED to other groups

Question 7

Why do we need accurate {measurements/records}? (1 reason)

Answer 7

1. to improve VALIDITY

ideally quantitative data (numbers) rather than qualitative data from questionnaires (more subjective)

Question 8

Why do we need a control group (e.g. placebo group for a CVD drug trial) with patients randomly assigned? (1 point)

Answer 8

1. To avoid bias

Question 9

Why do we need a Control? (3 reasons)

Answer 9

1. for comparison
2. shows that the {active ingredient in the drug/lifestyle factor} is having the effect
3. improves validity

Question 10

Why randomly assign patients to groups?

2 reasons

Answer 10

1. Characteristics of two groups similar, but participants placed randomly in groups
2. Removes bias - ensures the researchers do not influence results

Question 11

Studies must be ______ and ________.

Key Summary: Features of biological studies (e.g. CVD studies) checklist
7 features

Answer 11

valid

reliable

1. LARGE SAMPLE SIZE
2. Standardised method to allow REPEATS – MEANS AND SD
3. CONTROLLED VARIABLES controlled or recorded
4. REPRESENTATIVE SAMPLE e.g. males and females
5. QUANTITATIVE data
6. STATISTICAL ANALYSIS of data
7. CONTROL GROUP FOR COMPARISON – with people RANDOMLY ASSIGNED to each group to PREVENT BIAS