Biological Approach - Research Methods

Question 1

What does a correlation look for?

Answer 1

A relationship between two variables.

Question 2

What is a positive correlation?

Answer 2

When one variable increases so does the other.

Question 3

What is a negative correlation?

Answer 3

When one variable increases the other decreases.

Question 4

What type of graph are correlations shown on?

Answer 4

Scatter graph

Question 5

What is the value of a perfect positive correlation/

Answer 5

+1

Question 6

What is the value of a perfect negative correlation?

Answer 6

-1

Question 7

What direction does a positive correlation create?

Answer 7

/

Up from left to right

Question 8

What direction does a negative correlation create?

Answer 8

\

Down from left to right

Question 9

What are the 4 levels of measurement/types of data?

Answer 9

Nominal
Ordinal
Interval
Ratio

Question 10

What is Nominal data?

Answer 10

Most basic level of measurement

Used when data is put into tally charts/categories

Only tells us how many ppts picked each option

Doesn’t give an individual score for each ppts

Question 11

What is Ordinal data?

Answer 11

Used when data can be ordered eg 1st, 2nd, 3rd

Can’t tell the gap between 1st and 2nd etc

Always used with questionnaires

Gives us an individual score for each ppts

Question 12

What is Interval data?

Answer 12

The distance between each score has a meaning and equal value.
eg gap between 5-10cm is same as 20-25cm

0 is just another number on the scale, it does not mean there is nothing
eg 0 degrees c doesn’t mean there’s no temperature

Question 13

What is Ratio data?

Answer 13

The distance between each score has meaning and an equal value.

However, 0 does mean nothing.
eg 0 seconds to do something means it took no time

Question 14

What is a Type 1 error?

Answer 14

If you reject the null hypothesis and it is actually true

Happens when the level of significance is too lenient

Question 15

What is a Type 2 error?

Answer 15

If you keep the null hypothesis when your experiment did work. (when there is a significant difference)

Happen when the level of significance is too harsh

Question 16

What level of probability do we start at?

Answer 16

p <= 0.05

The probability the results are due to chance is equal to or less than 5%

(unless we’re trying to disprove someone else’s results. Then we start at p <= 0.01)

Question 17

What test do we use on correlations?

Answer 17

Spearman’s rho

Question 18

Strengths of correlation

Answer 18

• Useful as a preliminary research techniques, allowing a link to be identified that can be further investigated.
• Can be used for sensitive topics as no deliberate manipulation of variables is required.

Question 19

Weaknesses of correlation

Answer 19

• Correlations only identify a link, they don’t identify which variables causes which. A 3rd variable may be influencing the results that’s not considered.
• Lack of correlation may not mean there is no relationship, it could be non-linear.

Question 20

What are the 3 scanning methods?

Answer 20

CAT
PET
fMRI

Question 21

Describe a CAT scan

Answer 21

• Uses X-rays to take images of the brain
• person lays on a bed that slowly moves through the gantry.
• The x-ray source rotates around the gantry (Circular machine).
• After every full rotation a 2D slice image is formed, then the gantry moves slightly forward and it is repeated.
• After it is done, all images are fitted together to create a 3D image of the brain.

Question 22

Describe a PET scan

Answer 22

• Takes functional images of the brain
• A radioactive tracer attached to glucose is injected into the person.
• Needs to wait for the tracer to be absorbed.
• Areas that are most used will absorb more glucose/tracer.
• Person is on a bed in the PET scanner that slowly moves through it.
• Positrons are emitted due to the breakdown of the tracer, these emit gamma rays that are detected by the scanner.
• 3D image is created

Question 23

Describe a fMRI scan

Answer 23

• Uses a powerful electro-magnet focussing on blood flow
• Magnetic flow affects the magnetic nucleus of atoms and causes them to align in the same direction
• Tiny magnetic signals add up to create a signal that can be detected
• fMRI detects this blood flow and sees the more active areas, creating a functional image

Question 24

Strengths of CAT scans

Answer 24

• Less harmful than PET scans
• Can detect changes in structure (good for tumors/haemorrhages)
• Not painful or invasive

Question 25

Weaknesses of CAT scans

Answer 25

• fMRI gives clearer pictures

- Involves x-rays which can cause cancers

Question 26

Strengths of PET scans

Answer 26

• Reasonably non-invasive
• measures what it intends to
• can be repeated

Question 27

Weaknesses of PET scans

Answer 27

• Invasive due to injection
• Difficult to isolate brain functions precisely as behaviours can use multiple areas
• can be claustrophobic

Question 28

Strengths of fMRI scans

Answer 28

• Non-invasive unlike PET
• Virtually risk-free
• Can detect small features/measurements of the brain - measured more accurately

Question 29

Weaknesses of fMRI scans

Answer 29

• Can’t determine causation as doesn’t show the areas in the brain that are associated
• Only shows a localised area’s function not the overall communication
• Too much head movement can distort the image