Introduction Flashcards
define statistics
describing event amthematically
define observation
entity to be measured
define measurement
act of assigning numbers of observations systematically
define datum and data
a single measurement and plural
define constant
observations that have uniform values
define varaible
observations that have non-uniform values
define quantitative variable
observation that can be counted; values reflect difference in degree, ex. reaction time
define qualitative varaible
observations that can be categorized; values reflect difference in kind, ex. gender
define discrete variable
observations take separated values only, no values exist between, ex. family members
define continuos variable
infinite numbers of values exist between any two observations; where the number of decimals determines precision, ex. weight
define real limits
boundaries of intervale for scores from a continuous variables located between two adjacent scores
upper: 150.5
real: 150
lower: 149.5
define nominal scale
- grouping into categoires with equal attributes
- numbers are arbitrary
- qualitative and discrete
- unique
define ordinal scale
- observations are rank ordered
- numbers can have more or less of some attribute (intervals between = irregular differences)
- quantitative and discrete
ex. social economic status (low, med, high) - unique and order
define interval scale
- different magnitude of an attribute (equal distance between number = equal distance in attribute)
- arbitrary zero
- quantitative and continuos
- ex. degrees celsuis
- unique, order and equal intervals
define ratio scale
- equal amount of attribute from absolute zero
- true zero
- quantitative and continuos
- ex. degrees Kelvin
- unique, order, equal intervals and true zero
what are the 4 properties of numbers?
unique, order, equal intervals (add/subtract) and true zero (multiply/divide)
can you go from a ratio scale to ordinal and vice versa?
You can go from ratio to ordinal because you are going from high precision to low precision, but you cannot go the other way become you cant make something precise without it being precise to begin with.
define description statistics
used to describe, summarise and simplify a set of observations
- central tendency: typical score
- variability: spread of score
- correlation: the relationship between variables
define inferential statistics
used to infer characteristics about the population from a sample
what is the difference between population and sample?
the population is the complete set of observations where the sample is a subset of observations taken to represent the population
what is the difference between parameters and statistics?
the parameter describes the characteristics of the population using Greek letters, and statistics describes the corresponding characteristics of the sample using Roman letters
define sampling error
discrepancy between sample statistics and its corresponding population parameter. it varies from sample to sample but there will always be error no matter what
define commutative property of algebra
property of + and x, changing the order of terms does not change the sum or product
define associative property of algebra
property of + and x, changing the grouping of terms doesn’t change the sum or product
describe what Xij represents
Xij is the score for the iTH person on the jTH measure
- subscript i represents difference persons, ranges from 1 to n
- subscript j represents different observations, ranges from 1 to J
