Victoria Sinner
QUANTITATIVE METHODS – EXAM NOTES
Theoretical aspect:
- Theory: an interrelated set of variables formed into hypotheses that specify the relationship
among variables, with the purpose of explaining natural phenomenon.
- Theoretical rationale: provides an explanation or prediction about why and how variable X
(independent variable) would influence variable Y (dependent variable).
- Variable: a characteristic or attribute that varies among the people that are being studied.
- Hypotheses: tested with statistics whereas opinions are not, can be answered by TRUE or
FALSE, and are followed up by data.
o Two types of hypotheses:
▪ Null hypothesis (H0):
• No difference nor change.
• Never stated, always implied.
▪ Alternative hypothesis (H1):
• Statement of prediction.
• Actual research hypothesis.
o Goal is to accept one and reject the other.
• Can either be directional (going in a particular direction) or non-
directional.
- Spurious relationship is a relationship in which the IV and DV seem related but in fact are
not.
o Ex. Age of miss American and murders by steam.
- Confounding variables are variables that are not measured but might influence or explain the
observed relationship.
o Ex. Direct relationship between the number of chimneys and number of pregnant
women.
▪ The confounding variable is the number of citizens: the more citizens, the
more houses (and chimney’s) and the more pregnant women within a
community.
▪ The IV and DV are related through a 3rd variable that links them.
- Moderating variable (ex. Gender) affect the relationship between the IV and the DV, such that
the effect may be present for one group (males) and not for another (females).
o Moderation variables tell you for whom an IV affects the DV.
- Control variables are a special type of IV that research measure because they potentially
influence the DV – but not for certain.
- Intervening/mediating variables stand between the IV and DV and mediate the effects of the
IV on the DV.
o Mediating variables tell you how an IV affects the DV.
1
, Victoria Sinner
Operationalization, reliability, and validity:
- Operationalization → the process of defining or selecting the correct measurement of your
study. Quality of results depends on quality of measurements.
o The better the scales the better results you will obtain.
How to define measurements?
- You will make use of variables; these may be abstract:
o Press freedom, materialism, life satisfaction, life quality.
o These abstract concepts cannot be measured with one question.
o Characteristics like gender, educational level, nationality can be asked with one
simple question.
- To measure abstract concepts, we generally use a set of questions → scales.
o Scales contain multiple items, being questions or statements, which participants must
react to.
o For each item of a scale, an identical number of answer options should be provided.
o Scale scores can be calculated in two ways:
1. The scores on the separate items (questions/statements) can be summed or
averaged.
a. Summing the scores allows the categorization of the participant:
intelligence, autism, addiction, total number of hours spend on social
media.
b. Averaging the scores allows the interpretation of the scale with the
original answer option.
2. ..
o Some scales combine so-called positive and negative items. In such cases, the
negative items need to be recoded before the scale score is calculated.
▪ Statements arguing for low or high level of (…). One statement might argue
for a high level and the next for a low level, but the answer options remain
the same so in order to prevent them from contradicting or balancing each
other out we need to recode.
• If scores are (strongly disagree) 1-7 (strongly agree), when reverse
coding: 1=7, 2=6, 3=5 etc.
• Final score is calculated by determining the average of original and
recoded scores.
- What are the criteria for a good operationalization:
o You need to have a reliable measure and should always measure the same.
o You need valid measures; did it actually measure what you wanted it to?
o You need an objective measure; does it measure the same way irrespective of who
answers?
▪ Important to assess the scales internal consistency and content validity.
2
QUANTITATIVE METHODS – EXAM NOTES
Theoretical aspect:
- Theory: an interrelated set of variables formed into hypotheses that specify the relationship
among variables, with the purpose of explaining natural phenomenon.
- Theoretical rationale: provides an explanation or prediction about why and how variable X
(independent variable) would influence variable Y (dependent variable).
- Variable: a characteristic or attribute that varies among the people that are being studied.
- Hypotheses: tested with statistics whereas opinions are not, can be answered by TRUE or
FALSE, and are followed up by data.
o Two types of hypotheses:
▪ Null hypothesis (H0):
• No difference nor change.
• Never stated, always implied.
▪ Alternative hypothesis (H1):
• Statement of prediction.
• Actual research hypothesis.
o Goal is to accept one and reject the other.
• Can either be directional (going in a particular direction) or non-
directional.
- Spurious relationship is a relationship in which the IV and DV seem related but in fact are
not.
o Ex. Age of miss American and murders by steam.
- Confounding variables are variables that are not measured but might influence or explain the
observed relationship.
o Ex. Direct relationship between the number of chimneys and number of pregnant
women.
▪ The confounding variable is the number of citizens: the more citizens, the
more houses (and chimney’s) and the more pregnant women within a
community.
▪ The IV and DV are related through a 3rd variable that links them.
- Moderating variable (ex. Gender) affect the relationship between the IV and the DV, such that
the effect may be present for one group (males) and not for another (females).
o Moderation variables tell you for whom an IV affects the DV.
- Control variables are a special type of IV that research measure because they potentially
influence the DV – but not for certain.
- Intervening/mediating variables stand between the IV and DV and mediate the effects of the
IV on the DV.
o Mediating variables tell you how an IV affects the DV.
1
, Victoria Sinner
Operationalization, reliability, and validity:
- Operationalization → the process of defining or selecting the correct measurement of your
study. Quality of results depends on quality of measurements.
o The better the scales the better results you will obtain.
How to define measurements?
- You will make use of variables; these may be abstract:
o Press freedom, materialism, life satisfaction, life quality.
o These abstract concepts cannot be measured with one question.
o Characteristics like gender, educational level, nationality can be asked with one
simple question.
- To measure abstract concepts, we generally use a set of questions → scales.
o Scales contain multiple items, being questions or statements, which participants must
react to.
o For each item of a scale, an identical number of answer options should be provided.
o Scale scores can be calculated in two ways:
1. The scores on the separate items (questions/statements) can be summed or
averaged.
a. Summing the scores allows the categorization of the participant:
intelligence, autism, addiction, total number of hours spend on social
media.
b. Averaging the scores allows the interpretation of the scale with the
original answer option.
2. ..
o Some scales combine so-called positive and negative items. In such cases, the
negative items need to be recoded before the scale score is calculated.
▪ Statements arguing for low or high level of (…). One statement might argue
for a high level and the next for a low level, but the answer options remain
the same so in order to prevent them from contradicting or balancing each
other out we need to recode.
• If scores are (strongly disagree) 1-7 (strongly agree), when reverse
coding: 1=7, 2=6, 3=5 etc.
• Final score is calculated by determining the average of original and
recoded scores.
- What are the criteria for a good operationalization:
o You need to have a reliable measure and should always measure the same.
o You need valid measures; did it actually measure what you wanted it to?
o You need an objective measure; does it measure the same way irrespective of who
answers?
▪ Important to assess the scales internal consistency and content validity.
2
