Scientific Methods & Descriptive Statistics

Question 1

Define:

What is a standard definition for a p-value?

Answer 1

A p-value represents the probability of obtaining a test statistic as extreme as the one observed from our dataset given the assumption of the null hypothesis being true

In other words, if there is an extremely low probability of getting the result that you did under these conditions, then you have cause to reject the null hypothesis (since it is so unlikely to be true and for you to have gotten that particular test statistic)

Question 2

List:

Give four key ‘goals’ of psychological scientific research:

(‘Goals’ = potential post-research applications)

Answer 2

1. Describing
2. Predicting
3. Explaining
4. Controlling

(Human behaviour)

Question 3

Define:

Psychological Science

Answer 3

“Discovering how and why people think, feel and behave [in certain ways] through systematic accumulation of evidence”

(Source: Proffessor Matt Hammond, VUW, Lecture 1 Slides)

Question 4

Compare & Contrast:

Inductive vs. Deductive research methods

Answer 4

• Inductive research begins with collation of data which you then derive patterns/generalisations from in order to contribute to new/existing theories
• Deductive research concerns verifying/building upon pre-existing theories and testing hypotheses (which are generated before collecting data)

Both contribute to the ‘systematic accumulation of evidence’ as according to general models of scientific research

Question 5

List the missing labels for the ‘Model of Psychological Science’ pictured below

Note: This model also applies to other scientific research fields

Answer 5

1. Theory
2. Hypothesis
3. Data
4. Pattern Identification & Generalisation

A) Inductive Process
B) Deductive Process

Note that both inductive & deductive processes contribute to the scientific method, and this cyclical model allows for continuous systematic accumulation and refinement of evidence/knowledge

Question 6

According to Karl Popper, what TWO key things constitute a ‘good theory’?

Answer 6

A ‘good theory’ is testable and falsifiable

1. Testability = ability to be measured/assessed empirically
2. Falsifiability = ability to be refuted/’proven wrong’

Question 7

Define:

Theory

Answer 7

Theories are explanations for observed phenomena that are informed by scientific methods including carefully tested hypotheses and other solid data / evidence

Question 8

Define:

A method

(In the context of scientific research)

Answer 8

The process(es) by which we go about testing predictions / hypotheses

Question 9

Describe:

Based on the model below, the kind of data you cannot generate theories from?

Answer 9

‘Exceptional events’

These are impossible to derive meaningful patterns or generalisations from, which are the ‘bridging’ step between ‘data’ and ‘theory’

Question 10

Identify:

FOUR key types of research designs

(According to the PSYC232 Course)

Answer 10

1. Questionaire/Survey
2. Naturalistic Observation
3. Experimental Design
4. Case Study

Question 11

Identify:

Case studies are unique because they tend to…

Answer 11

• Involve small ‘N’s (i.e. an individual, group, community, etc.)
• Be more inductive
• Result in data that is too unique for any initial generalisation/broader-spanning pattern recognition

Question 12

True or False:

We can prove our alternative hypothesis to be true if our data returns a statistically significant p-value

Answer 12

False

Observing statistical significance in the data gives us cause to reject the null hypothesis, but can never prove the alternative hypothesis (since we are finding evidence against the null hypothesis and not for the alternative)

Question 13

Fill-in-the-Blank:

Both ____ and ____ scales have equal distances between each of their points of measurement.

However, ____ scales have no meaningful zero point and cannot use phrases such as ‘double’ or ‘half’ to compare its measurement points. A ____ scale though does have a ‘true zero’ (the absence of ‘x’) and can have measurements compared in those ways.

Answer 13

Both interval and ratio scales have equal distances between each of their points of measurement.
​
However, interval scales have no meaningful zero point and cannot use phrases such as ‘double’ or ‘half’ to compare its measurement points. A ratio scale though does have a ‘true zero’ (the absence of ‘x’) and can have measurements compared in those ways.

Interval scales can instead describe points as ‘more/less’ than another.

Both scales may use means for statistical analysis

Question 14

Define:

Standard Deviation

Answer 14

‘Standard Deviation’ is used to describe the extent to which individual data points vary from the mean (of the population ‘N’, or the data-set/sample ‘n’ )

Question 15

Define:

What is the central limit theorem?

Answer 15

The central limit theorem states that if you have a population with mean μ and standard deviation σ and take sufficiently large random samples from the population with replacement , then the distribution of the sample means will be approximately normally distributed

(Source: Boston University)

Note: the general minimum value of ‘n’ for this to apply is n = 30

Question 16

Epistemology is concerned with what concepts?

Answer 16

Epistemology involves theories about knowledge itself, such as whether it is valid, or the methods we utilise in the search for it

What do we know? How do we know it? And do we truly know it?

Question 17

Explain:

Why are means/averages not always entirely adequate to describe humans?

Answer 17

No one is perfectly average, and so variability is also vital when describing humans and their behaviour.

Think of the need to have adjustable seats - (you would struggle to find someone who fits the population average for every single bodily dimension these things are designed around!)

Question 18

Define:

Operationalisation

Answer 18

This is the process by which researchers specify how they quantify/measure particular constructs

(e.g. quantifying ‘stress’ by indicators of physical arousal such as increased heart-rate, skin-conductance, etc.)

Question 19

Fill-in-the-Blank:

Interval and ratio scales are used for ____ variables

Answer 19

continuous

Question 20

Fill-in-the-Blank:

____ data increases/decreases in an order without mathematically meaningful distances between each point

Answer 20

Ordinal

(aka ‘Ranked’ data)

Because the extent/magnitude of difference between each piece of data is not clear, we tend not to use it as much in Psychological scientific research

Question 21

Compare & Contrast:

Reliability & Validity

Answer 21

Reliability refers to how consistently you achieve a certain outcome/result, whereas validity questions whether you have appropriately measured something

Question 22

Define:

What is item reliability?

Answer 22

Item reliability concerns whether or not each item of a scale measures the same thing

(i.e. internal consistency)

Question 23

Define:

What is test-retest reliability?

Answer 23

Test-retest reliability concerns whether or not your measurements remain consistant across multiple repeats

(This can be improved by measuring things in the same manner, with the same equipment each time, etc.)

Question 24

Define:

What is observer/rater reliability?

Answer 24

Observer/rater reliability concerns whether or not people make consistent ‘ratings’/’value judgements’ etc. with each other

(This can be decreased significantly if ambiguity in how one may measure something is increased.
Think of Amazon reviews where one person rates a product highly because it was the quality they were expecting, but another person rates it poorly because it arrived slowly - these two people are giving ratings with entirely different sets of standards in mind to each other)

Question 25

Define:

What question embodies the concept of construct validity?

Answer 25

‘Do our measurements make sense with the initial theory?’

Question 26

Define:

Internal validity concerns…

Answer 26

…whether or not our study design was the most appropriate for addressing the research question

Question 27

Define:

External validity concerns…

Answer 27

…whether or not our findings coincide appropriately with other findings and concepts in the real world beyond our lab setting

Question 28

Define:

Statistical validity concerns…

Answer 28

…whether or not the statistical test(s) we have chosen are appropriate for the original research question and measurement(s)