Intro

Question 1

A Discrete variable

Answer 1

variable can only take on a small set of possible values e.g., number of siblings

Question 2

External validity/ Generalisation

Answer 2

degree to which the results of the study can be generalised to the target population. Internal validity refers to whether a study accurately measured what is claimed to measure

Question 3

◦ For populations descriptive statistics are referred to as parameters

Answer 3

◦ For samples they are referred to as statistics

Question 4

Nominal scale is the lowest level of measurement what is an example?

Answer 4

Gender male =1 Female = 2

Question 5

Ordinal scale?

Answer 5

order and magnitude 1sr 2nd 3rd ( cannot assume dsitance is the smae allows for comparisons

Question 6

Interval scale or ratio scale has a true zero?

Answer 6

Ratio. e.g height, weight, gpa , no of children, income

Question 7

Measurement error is any factor that can inflate or deflate a person’s score on a dependent measure. What are the two types of measurement error?

Answer 7

Random error and systematic error

Question 8

Random error

Answer 8

any factors that randomly affect measurement of the dependent variable across a sample e.g., participants’ mood. Does not have consistent effect across sample. Scores increase or decrease randomly.
Adds variability to the data but does not affect average performance of the sample
considered noise. we can minimise the effects of random error by adopting a more conservative significance level

Question 9

Systematic error – a Bias

Answer 9

any factors that systematically affect measurement of the dependent variable across the sample
e.g., traffic noise that will affect all participants’ scores
errors will be consistently positive or consistently negative
Unlike random error, effects cannot be minimised by adopting a conservative alpha level

Question 10

internal validity - The extent to which a causal conclusion from a study’s results is warranted

Answer 10

• No other variable except the one we are studying caused the result
• minimising systematic error e.g., pay rates and productivity
• confounding (extraneous) variables
• uncontrolled variables that may affect the outcome of a study e.g., personality, motivation, competitiveness

Question 11

How can we improve external validity?

Answer 11

 Random selection - random sampling is essential for external validity
 reduce attrition
 clearly describe differences in context between current study and other studies
 replicate – variety of places, people and times

Question 12

How can we imrove internal validity?

Answer 12

Random assignment - how participants assigned to groups. related to design. Absence of systematic bias

Question 13

What is operationalisation? or operational definition

Answer 13

how an abstract construct is defined it terms of how it will be measure or manipulated in research e.g exercise no of minutes per week at the gym vs steps taken per day