Lecture 1 Flashcards
Define descriptive statistics
Stats that organize, summarize, and communicate a group of numerical observations
Ex. mean, DS
Define inferential statistics
Stats that use sample data to make inferences about the larger population
What is the study/experimental cycle?
Populations have a sample taken from them, then a study is done on the sample and the results are applied to the bigger population
If p is less than 0.001 then it is _______ due to chance
likely
Define variable
Observations of physical, attitudinal, and behavioural characteristics that can take on different values
Ex. height - easy to measure
extraversion, intelligence, self-esteem, creativity - abstract and difficult to measure
Define discrete observations
Take on only specific values (whole numbers). No other values can exist between these numbers
Continuous Observations
can take on a full range of values (numbers out to several decimal places); an infinite number of potential values exist
4 types of variables to quantify observations (discretion/continuity)
Nominal
- always discrete
- never continuous
Ordinal
- always discrete
- never continuous
Interval
- both discrete and continuous
Ratio
- mostly continuous
- sometimes discrete
Define nominal variables
used for observations that have categories or names as their values
ex. gender, chromosomes, hair colour, nationality, race, religion, beliefs
Define ordinal variable
used for observations that have rankings (i.e., 1st, 2nd, 3rd,…) as their values
Define interval variable
used for observations that have numbers as their values; the distance (or interval) between pairs of consecutive numbers is assumed to be equal
- no true 0 point
CV ex. temp (0 is still a temp)
DV ex. IQ scales
Define ratio variable
a variable that meets the criteria for an interval variable but also has a meaningful zero point
ex. temp in kelvin, reaction time, weight
define scale variable
a variable that meets the criteria for an interval variable or a ratio variable
- #’s mean something
define independent variables
has at least two levels that we either manipulate or observe to determine its effect on the dependent variable (treatment)
define dependent variable
the outcome variable that we hypothesize to be related to or caused by changes in the independent variable (outcome)
define confounding variable
any variable that systematically varies with the independent variable so that we cannot logically determine which variable is at work
define reliability
refers to the consistency of a measure
repeated testing = same results
define validity
refers to the extent to which a test actually measures what it was intended to measure
define hypothesis testing
the process of drawing conclusions about whether a particular relation between variables is supported by the evidence
define operational definition
specifies the operations or procedures used to measure or manipulate a variable
ex. stress can be operationally defined by blood pressure, heart rate, and cortisol levels, which can all be measured with a polygraph test
define correlational studies
correlation - an association between 2 or more variables
- causal statements to be made
- potential confounding variables
define experiment
a study in which participants are randomly assigned to a condition or a level or one or more independent variables
define random assignment
every participant has equal chance of being assigned to any of the groups or conditions
between-groups design
an experiment is which participants experience one and only one level of the independent variable
- more subjects required
