1theory
statement about the possible casual relationship between two or more concepts
2hyptotheis
theory based statements about a realtionship
3null hypothesis
what we see if the theory is wrong
4hypotheis testing
how we evaluate hypotheis
5dependent varriable
thing to be explained, the effect, y
6independent varribale
thing that does the explaining, cause, X
7rules of the road for scientifc knowledge
1. make thoeries casual
2. dont let data drive theory
3.consider emprical evedince
4.avoid normative statements
5. pursue generalilty and parasiomny
8what makes a good theory
casual
testable
genreral
parasaimounis
new
nonobvious
9casual
implying casuaulity, that these tings cause one another
10correlation
statisical measure of covarration which summarizes the direction and strength of the linear realstionship between two varribales
11covary
when two varriables varry together
12dependent varriable
varriable for which at least some of the varration is theorized to be caused by one or more indepednent varriables
13emprical
based on real world observation
14hypotheis testing
the act of evualauting the empicrical evedince in order to determine the level of support for the hypotheis verus the null hyptheis
15measure
process by which abstract concepts are turned into real world observations
16negative relationship
higher values of the independent varriable tend to coincide with lower values of the dependent varriables
17normal science
scetific research that is carried out under the shared set of assumptions and accepted theories of a paradigm
18nomrative statements
statements about how the world ought to be
19operationilize
another word for measurement, when a varribale moves from the concept level in a theory to the real world measure for a hypotheis test it has been operationilized
20paradigm shift
when new fidnings challenge the conventioal wisdom of a paradigm to the point where the set of shared assumptions and accepted thoeries is redefined
22posistive realtionship
higher values of the independent varriable tend to coincide with higher values of dependent varribale
23theoritical model
the combination of independent varribales, the dependent varribable, and the casual relationship that are theorized to exist between them
24cross-sectional measure
measure for which the time dimension is the same for all cases and the cases represent muliple spatial units
25spatial dimesions
the physical units on which the varriable is measured
26time dimeinsions
the point or points in time at which a varribale is measured
27time-series measure
measure for which the spatial dimesion is the same for all cases and the cases represent muliple time units
28transistative
mathimaticial relationship such that if A is greater than B, and B is greater than C, A must also be bigger than C
29bivarriate
involving just two varribales
30confuding varribale
varriable that is correlated with both the independent and dependent varriables and that somehow alters the realstionship between those two varriables
31spurious
not what it appears to be, false
324 hurdles to establishing causualilty
1. is there a credible casual mechainism that connects X to Y
2. can we rule out the possiblilty that Y causes X
3. is there covarration between X and Y
4. have we controlled for all confunding varribales, that might make the relationship spurious
33cross-sectional observational studies
reserch desgins that focuses on varration acorss spatial units at a single time unit
34data set dimesions
the spatial and time units that define a data set
35expirements
research desgins in which the researcher both controls for and radomly assigns values of the independent varribale to the particants
36placebo
fake stimlous given to a control group
37radom assigment
when the particpants for an expirement are radomly assigned to one of the several possible values
38radom sampling
method for selecting indivual cases for a study in which every member of the underlying population has an equal probabbility of being selected
39research desgin
the stragies that a researcher employs to make comparsions with the goal of evaulating causal claims
40spatail unit
the physical unit that froms the baisis of obsevration
41time-series-observational studies
research desgins that focuses on varration within a single spatial unit over muliple time units
42measurement bias
the systematic over-reporting or under-reporting of values for a varribale
43reliablilty
the extent to which applying the same measurment rules to the same case or observation will produce identicial results
44validity
the degree to which a measure accurately represents the concept that it is supoosed to measure
45central tendeancy
typical values for a particular varriable at the center of its distrbution
46dispersion
the spread or range of values of a varribale
47histogram
visual depection of the distbrution of a single varribale that produces two-dimensional figure in which the horizontal displays the varriables and vertical displays the relative frequency of cases
48kernel density plot
visual depection of the distrbution of a single varribale based on a smoothed calcualtion of the denisity of cases across a range of values
49least-sqaure property
property of the mean value for a single varribale y, which means that the sum of the sqaured diffrences between each y values,yi, and some value for c
50mean value
average of a varribale equal to the sum of all values of y across indiviauls cases of y
51median value
value of the case that sits at the exact center of our cases when arrnaged from lowest to highest
52mode
the most frequnelty occuring value of a varribale
53ordinal varriable
varriable for which we can make universally holding ranking distctions acorss the varriable values, but metric does not have equal unit diffrences
54skewness
statisical measure of indicating the symmtery of the distrbution around the mean
55standard devation
statsicial measure of dispersion of a varribale around its mean
56varriance
statisical measure of the dispersion of a varribale around its mean
57zero-sum propery
property of the mean value for a single varriable y which means that the sum of the differnce between each y value, yi, and the mean value of y, ybar, is equal to zero
58population
data for every possible revleant case
59control for Z
isolate, account for
60casual theory is
directional, (x-y,y-x, both, neither)
61levels of anaylisis
what youre comapring, comapring indivauals to indivuals, comparing aggerate quantaties
62how to establish causuality in observational studies
statisical contorls. (if we cannot dorectly equate groups the way an expiremnt does with radom assignment, in observational studies we work to contorl for other possible causes of y)
63cross- sectional
at one point in time
64impoarant steps of measurment
1. have a clear goal
2. develop a measure which is both reliable and valid
3. know your data
652 properties of measurment
1. realiablilty
2. validity
66levels of meausrment
catergoical
ordinal
continous
67meausres of centeral tendency
mode
median
mean
68properties of the mean
zero-sum
least squares
69measures of dispersion
range (high score-low score)
IQR (rnage between 25 and 75)
standard devation