The what and why of statistics Flashcards
What’s a statistic?
a numerical value that characterises the sample or population from which it was derived
What’s statistical inference?
the theory, methods and practice of forming judgements about the parameters of a population and the reliability of statistical relationship, typically on the basis of random sampling
What is empirical research?
- research based on info that can be verified by using our direct experience
- to answer research questions we can’t rely on reasoning or speculation
What’s a hypothesis?
- derived from theory
- specific and exact statement about the relationship btw variables
- stated in terms of variables
What’s a variable?
- any trait that can change values from case to case
- 2 types: dependent (effects/outcomes) and independent (causes)
What’s the difference btw a population and a sample?
- population: collection of all possible cases of interest
- sample: carefully chosen subset of a population; used for study and analysis
What are descriptive stats?
procedures that help us organize and describe data collected from either a sample or a population
What are inferential stats?
procedures used to reach conclusions about a population from data collected from a sample
What are the 3 levels of measurement for a variable?
- Nominal
- Ordinal
- Interval-ratio
What are nominal levels of measurements?
- scores or categories that are non-numerical
- lowest level of measurement available
- only relative sizes of categories can be compared
eg. gender, race. religion
What are ordinal levels of measurement?
- scores or categories that can be ranked from high to low
- categories can be described as more or less with respect to each other
- we don’t know the distance from one score or category to the next
eg. social class, Likert scales
What are interval-ratio levels of measurement?
- measured as numbers
- scores can be ranked from high to low
- we can quantify distance btw different scores
eg. income (in $), number of siblings, years of education
