Research Methods and Statistics - BIOLOGICAL

Question 1

What are correlational designs?

Answer 1

Involve comparing data from the same participant or two sets of data

Question 2

What are the possible relationships between the two sets of data?

Answer 2

Scoring highly on one measure

Scoring highly on two measures

Question 3

What are the two correlations types?

Answer 3

Positive and negative correlations

Question 4

What are positive correlations?

Answer 4

When one score increases, the other also increases

Question 5

What are negative correlations?

Answer 5

When one score increase, the other decreases

Question 6

What is important to know about correlational designs in terms of variables?

Answer 6

no independent or dependent variables but two variables of equal importance

Question 7

What is important to know about correlational designs in terms of hypotheses?

Answer 7

The hypothesis put forward will be not about a difference between variables but a relationship between two variables

The hypothesis could be directional (predicting a positive or negative correlation)

Question 8

What is important to know about correlational designs in terms of scatter diagrams?

Answer 8

scatter diagram can show whether a correlation is positive/negative/neither as correlational designs involve a lot of controls which is harder to do when studying relationships

Question 9

What is important to know about correlational designs in terms of sampling?

Answer 9

sampling with random sampling being the most representative of the target population

do not involve ‘randomised to groups’ as each participant does both conditions

Question 10

What is important to know about correlational designs in terms of control groups?

Answer 10

are unlikely to apply to correlational designs as they look at relationships, not cause-and-effect conclusions.

Question 11

What are the strengths of Correlational designs?

Answer 11

Initial relationships can be discovered through this flexible design which could uncover new research

Same people provide both sets of data, not affected by individual differences

Question 12

What are the weaknesses of correlational designs?

Answer 12

They only indicate a relationship, not a cause-and-effect relationship

The measures may not provide valid data as correlations can use data from unnatural measures

Question 13

How are correlational designs analysed and displayed?

Answer 13

analysed by Spearman’s Rho and can be displayed using a scatter diagram

Question 14

What is the procedure for a CT scan?

Answer 14

Its procedure is for the individual to lie on a moving platform to be passed through a scanner or for the person to lie still so that the scanner can move past them - sometimes a dye (e.g. iodine or barium) is used for highlighting purposes. It can take from a few minutes to 30 minutes - a MRI scan can give better images and a PET scan can look at brain functioning; CAT scans are purely used on a medical basis and check brain damage.

Question 15

What are the strengths of CT scans?

Answer 15

Less harmful than PET scans (radioactive tracer) although X-rays can be damaging so are used infrequently

Can detect changes in physical structures to a good level and so is valuable when looking for tumours, haemorrhages or calcification as it produces a 3D image which aids diagnosis

Modern approach of helix formation allows different angles of an area of interest to be studied -helps build an overall image when looking at damage

Not painful and non-invasive although this is not the case if a dye is used.

Question 16

What are the weaknesses of CT scans?

Answer 16

MRI gives a clearer picture when examining causes of headaches (for example) or infection

Involves x-raying which can cause damage and cancer, and so would not be recommended for research purposes

Question 17

What is the procedure for a PET scan?

Answer 17

PET scans can be used to study the brain as it picks up ‘hot spots’, enabling researchers to figure out which parts are working at a particular time. A radioactive tracer is added to chemicals (normally glucose) and injected into a vein in the arm, where it provides small positively charged particles (positrons) which give recorded signals - where the glucose is used up indicates that area of the brain to be active. These recordings are displayed as images which are recorded.

Question 18

Can PET scans be used to study blood flow?

Answer 18

Yes - It can also be used to study blood flow as increased blood flow to a specific region of the brain indicates that region to be active during a particular activity e.g. talking which can be detected by the scan. It is this way, we can figure out the functions of different parts of the brain e.g. language uses many regions of the brain and researchers can ask someone to think of words, read words aloud and speak etc. to define which regions are used for language purposes

Question 19

What are the strengths of PET scans?

Answer 19

Reasonably non-invasive: although the individual must inject the radioactive tracer which is invasive, the images are taken outside the body which is less dangerous and distressing than surgery

Validity: it measures what it says it measures e.g. confirmed what they assumed was the area of speech (by examining the bodies of deceased individuals with speech problems) was the area of activity (Broca’s area)

Reliable: it can be repeated with the same conclusions being found

Question 20

What are the weaknesses of PET scans?

Answer 20

Injecting a radioactive tracer is invasive and so there are ethical implications, meaning ethical guidelines must be strictly followed (informed consent obtained, and a justifiable reason for the procedure)

The scan can cause some people distress as it can be a claustrophobic experience which must be fully explained to the participant

Although activity shows quite clearly on the image, it’s hard to isolate specific brain functions precisely and so can criticise validity

Question 21

What is the procedure for MRI scans?

Answer 21

A strong magnetic field is passed over the body (possibly within a tube) in a noisy but painless experience, and the patient must keep as still as possible as the scan can be affected by movement. The effect of the magnetic field is measured, images produced and interpreted: as the magnetic field ‘passes over the body’, it excites hydrogen atoms within the body which can be detected. Before a MRI scan is carried out, a dye (contrast medium) is injected to highlight the body’s organs and other relevant areas.

Question 22

What are the strengths of a MRI scan?

Answer 22

Validity: what is found in the scna often coincides with reality, making them accurate in checking for abnormalities in the brain and body

Compared with surgery, MRI scans are non-invasive (apart from the injected dye) and therefore is more ethical

Can be replicable, as it is repeatable with the same conclusions being found - scientific method

Preferred over CT/CAT scanning as it is less harmful

Question 23

What are the weaknesses of MRI scans?

Answer 23

Stressful as an injection is given, noisy environment, and could make the participant feel as if they were being ‘closed in’ on.

Only measures particular things e.g. soft tissue or body organs but does not measure brain activity so can say knowledge obtained from MRI scans are limited

Question 24

What is the procedure of an fMRI scan?

Answer 24

same as a MRI

Question 25

What are strengths of fMRI scans?

Answer 25

No danger from radiation (unlike CT scanning and PET scans)

Detection of changes in blood flow are very precise and so slight changes can be detected, meaning it is useful for detecting issues around strokes, brain structure and functioning

Question 26

What are the weaknesses of fMRI scans?

Answer 26

Cannot look at the actual receptors of neurotransmitters like PET scans can

Problems can arise e.g. too much head movement can distort the image

It is not easy to get a baseline measure as fMRI scans are used to see certain types of information processing taking place within the brain, however automatic functions e.g. breathing do also require processing

Risks e.g. to those with pacemakers or generally due to issues like claustrophobia