STATS EXAM 1

P value

Critical value

Statistical signifcance

Z score

Descriptive statisics

Used to organize and describe characteristics of data (frequency, mean, standard deviation, averages, central tendency and variability)

Empirical data

Collected through direct observation

Inferential statistics

Used to make inferences, generalizations or assumptions about a population (correlation, t test, ANOVA, regression, chi-square)

Sample

Portion of a population selected for a study intending to represent the population

Random sampling

Randomly deciding who is selected in the population for a study to account for all characteristics of a population

Sampling error

picking two samples that differ by chance—a measure of how well a sample approximates the characteristics of a population

Random assignment

Randomly assigning people to group once hidden differences are equalized in the context of the study

Paradigm

Example or prototype in reserach

Parameters

Population parameters are estimated with sample statistics since it is virtually impossible to study an entire population

Representative sample

A sample whose distribution of varying characteristics matches that in the broader population of interest

Variable

Construct or element in research that can take on more than one value 

Operationalization

Process of defining how a variable will be measured (for purpose of replication)

Conceptual varaible

Abstract ideas of interest in research (not always directly observable and/or might be observed multiple ways) 

Measured variable

Empirical (i.e observed) indicator of a conceptual variable. Concrete representation of an abstract idea or thought based on its operational definition

Average

A value that best represents an entire group of scores

Measures of central tendency

Mean, median mode

Skew

To significantly distort in the case of certain values

Mean

Average sum of values divided by values in the group (add all values than divide them by nunber of values)

Median

Most middle scores, list values from highest to lowest, vice versa, (even set of scores, the median is the mean of the two middle values, insensitive to extreme scores, doesn’t utilize all scores)

Mode

Value that occurs most frequently

Scale of measurement

Rules or levels outcomes are observed by

Nominal level of measurement

Defined by the characteristics by an outcome that fit into one and only one class or category, also called qualitative or categorical variable, mutually exclusive (Only mode can be used)

Ordinal level of measurement

Categories are ordered in terms of size or magnitude, interval each category represents is not equal, each level from another is not an equal span (use mode, median and mean *with caution*)

Interval level of measurement

Categories are ordered and do represent roughly equal intervals, no absolute zero point (ratios of scores aren’t meaningful) —mode median and mean