Discovering Statistics; Chapter 1 Flashcards
When are qualitative methods of research used?
When the experimenter needs to analyse language.
Briefly outline the research process.
Research question -> generate theory -> generate hypothesis (identify variables) -> collect data to test theory (measure variables) -> analyse data (graph data and fit a model)
What are variables?
The ‘things’ in an experiment that change or don’t change which are measured by the experimenter.
What is a theory?
An idea or explanation based on observations in a natural setting.
What is a hypothesis?
A prediction from a theory.
What is falsification?
Act of disproving a hypothesis/theory.
What is the independent variable?
A variable where the value is not dependant on other variables.
What is the dependant variable?
The variable where the value depends upon the manipulation of the experiment.
What is the predictor variable?
A variable though to predict an outcome.
What is the outcome variable?
It is a variable which is thought to change as a function of changes in the predictor variables.
What are categorical variables?
Categorical variables are entities divided into distinct categories.
What are continuous variables?
Where entities get a distinct score.
What is measurement error?
The discrepancy between the numbers used to represent what we’re measuring and the actual value of what we’re measuring.
What is validity?
The extent to which the measuring instrument measures what it intends to measure.
Depends on reliability.
What is reliability?
The extent to which the measuring instrument finds the same results in repetition.
What is correlational/cross-sectional research?
Where research a observe what naturally occurs without interference.
What is longditudinal research?
Repeatedly measuring the same people over a long period of time.
What is ecological validity?
How a studies results can be generalised to the public.
What is tertium quid?
A third person or thing interfering with the observation.
What are confounding (or extraneous) variables?
Variables from the real world which can influence results (such as time of day)
When are quantitative methods of research used?
When numbers are involved in the data.
What are between group/independent measures experiments?
Different groups do every condition.
What are within subject/repeated measures experiments?
One group does all experimental conditions.
What is systematic variation?
The variation that occurs due to the experimenter doing something in one condition, but not the other.
What is unsystematic variation?
The variation that results from random factors that exist between experimental conditions (eg. time of day). We aim to keep this variation as small as possible through randomization.
What are practice effects?
Performing differently in the second condition due to familiarity. It is overcome with counterbalancing (AB/BA).
What are boredom effects?
Performing differently in the second condition due to boredom/tiredness.
What is a normal distribution of the data?
Data displayed as a bell-shape curve on the graph.
What is a positive skew?
Frequent scores gathered to the left of the graph.
What is a negative skew?
Frequent scores gathered to the right of the graph.
What is kurtosis?
The ‘pointyness’ of the curve.
What is leptokurtis?
Otherwise known as positive kurtosis; a tall curve.
What is platykurtis?
Otherwise known as negative kurtosis; a flat curve.
What is the central tendency?
The value calculated to assess where the centre of frequency distributions lie.
What is the mode?
The score that occurs the most frequently.
What is bimodality?
A set of scores that has two scores which are equally as frequent as each other.
What is multimodality?
A set of scores that has three or more scores which are equally as frequent as each other.
What is the median?
The middle score.
What is the mean?
A measure of central tendency. Calculated by the sum of scores being divided by the total number of scores.
What is the range?
The largest score - the smallest score.
What is the interquartile range?
Range of the middle 50% of scores (upper quartile - lower quartile).
What is the lower quartile?
The median of the bottom 50% of scores.
What is the upper quartile?
The median of the top 50% of scores.
What is the deviance?
The difference between the raw score and the value of the mean.
What is the equation for a z-score?
(score - mean) / standard deviation.
