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Definition
Statistics
 Numerical Summarize measure computed on data from a sample
 Numerical Characteristics of a Sample
 Ex: Mean, TTest, ZScore


Definition
Population
 A target group of participants about which the researcher will make decisions
 Ex: OU Students, Am Citizens, 1999 Honda Civics

Definition
Population: Characteristics (3)
 1. Large
 2. Unobtainablenever can collect all data (CENSUS)
 3. Hypotheticalwe make assumptions because 1 &2 are as well as people are always changing

Definition
Sample
Subgroup of Population
Small group of participants from which the researcher makes decisions about the population

Definition
Random Sample
Random Sampling eliminates biases

Definition
Variables
 Quantity or property that takes on different values
 Continuousinfinite # of values
 Discretefinite # of values

Definition
Independent Variable
variables manipulated by researchers

Definition
Dependant Variables
behavior observed and measured

Definitions
Extraneous Variables
 Not IV or DV but might effect the study
 a variable we need to control
 Ex: Gender

Ways to control Extraneous Variables
 1 Randomize participants into groups
 2 Keep all participants constantion EV
 3 include EV in the design of experiment

Definition
Types of Experiment Designs
 True Experiment
 Observational Research
 QuasiExperiemtn

Definition
True Experiment
 Manipulation of Independent Variable
 Randomization of Group
 Optional methods to control Extraneous variables
 Causal relationship between IV and EV
Problems:Taking it to the streets

Definition
Observational Research
 Predictive relationships
 Observation of prediction and criterion variable
 No Manipulation
 Minimal control of EV
 Predictive relationship btwn prediction of variable and criterion variable

Definition
Quasi Experimental Design
 Manipulation of IV
 No Randomization
 Some control of EV
 degree to which we can attribulte a causal relationship depends on consideration of possible outcomes
 1)internal validityapplies outside the lab
 2)External validityapplies in the lab only

Definiton
Scale of Measurment
 Nominal
 Ordinal
 Internal
 Ratio

Definition
Nominal
 Data with identity only
 Qualitative in nature
 Ex: Gender, religion

Definition
Ordinal
 N+O
 Identity
 Order
 Ex:Ranking, Year in School, Scales!!!

Definition
Interval
 N+O+I
 Identity
 Order
 Equal Distance on # Scale
 Ex: Temperature, Not Scales!

Definition
Ratio
 N+O+I+R
 Identify
 Order
 Equal Distance
 True point 0
 Ex:Kelvin Temp, Height, Weight

Definition
Skew
 If Both halves of the distribution is said to be Normal Distributed
 Departure from Symmetry is defined as Skewness

Definition
Measures of Central Tendency
 A typical or Representative score
 Scores that represents the middle of the distribution
 Ex:Test scores in class, Average age

Definition
Measure of Central Tendency
Statistics and Parameters
 Mode:Most frequestn score
 MedianMiddle valuse in distribution50% below/above
 Meanarithmetic average= Sum X/N
 Parameter Mean µ
 Statistic Mean= X_bar

Definitions
Measures of Variability
 Spread
 Dispersion of the Scores
 EX: Variance, Standard Deviation,Range, Biased Sampled Variance

Definition
Measure of Variability
Statistics and Parameters
Variance
 Variance
 Parameter = σ^{2}
 Statistic= S*^{2 }and S^{2}

Definition
Measure of Variability
Stats and Para
Standard Deviation
 Standard Deviation
 Parameter= σ
 Statistic= S* & S

Definition
Measure of Variablity
Range
 Range
 Maximize mean
 *Point of the class*
 Stat= obtain from sample
 Parameter= Exists in Population

Definition
Measure of Variability
Biased Sample Variance
 Biased Sample Variance
 Bias to small on average
 Bias sample variance (s*^{2}) average^{2} Deviation from mean

Definition
ZScore
Z=SOMETHING minus MEAN divided by STANDARD DEVIATION

Definition
ZScore
Characteristics
 Each X to a Z
 Mean= Z_bar=0
 Variance= s_{z}^{*2}=1
 Standard Deviation= s_{z}*=1
 Transformation to ZScore does not change the shape of the distribution

Definition
Normal Distribution
 1 Symmetricsame on both sides
 2 Smooth1 hump
 3 Unimodal1 mode
 4 Bell Shaped
 Tails of distrubutionnever touch Xaxis
 Mode = Median=Mean
 Infinite # of score values (continuous variable)

Definitions
Correlations
 The degree of linear relationship between two variables
 ↑↑ ↑↓ ↓↓

Definition
Correlation
Causation

Definition
Strengh of Association
 r = I 1 I
 Closer to 0= Weak
 Closer to 1 or 1 = Strong

Definition
Regression
 The area of statistics where a researcher is concerned with predicting one variable from another
 Describing data for two variables

Definition
Regression
Characteristics
 Y'= predicted score of criteron variable
 b=slope of the line= Rise/run (Rise over Run)
 X=score of the predictor variable
 a= Yintercept of the line
 (Y=observed point, Y' what come out of formula)

Definition
Sample Space
 Group of data points representing all possible outsomes of an experiment
 Ex: A population of a deck of Cards

Definition
Elementary Event
 Single member in a sample space
 (Ace of Diamonds in a deck of cards)

Definition
Event
 Any group of elementary events
 Ex: Kings

Definition
Probability
# in the event divided by total # of possible outcomes

Definition
Conditional Probability
 A probabilit of one event that is dependent of another event
 P(A/B)

Definition
Independence
One event occuring does not change the probability of another event occuring

Definition
Multiplication (AND) Rule
 INDEPENDENT
 P(A&B)= P(A) X P(B)
 NOT INDEPENDENT
 P(A&B)= P(A/B)*P(B)=P(A)*P(B/A)

Definition
Mutually Exclusive
 When A & B do not have an elementary event in common
 P(A&B)=0

Definition
Addition (OR) Rule
P(A or B)= P(A) + P(B) [P(A&B)]

Definition
Sampling Distributions
Distribution of all possible values of a statistic, sample mean, st devi, or variance

Definition
Sampling Distribution
Shape
sahpe of the mean is approximated by normal distribution

Definition
Sampling Distribution
Statistics and SD
Every statistic has a sampling distribution

Definition
Sampling Distrubution
Purpose
 1 Pop and Param are typically unknowwe want to make decision about them
 2 Sample and Stats are know and stats are estimates of parameter can't say stats is = to param and make decisions directly b/c stats have variability
 3 Samp dis of stats is used to quantify into probability the info about variability of the stat

Definition
Central Limit Theorem
as N (Sample size) approaches infinity, the sampling distribution of X_Bar approches normality
N=30 is best (closest to infinity)

Application/ Identification
Statistics vs. Parameter
s* vs. σ
 Stats are used to estimate Parameter
 Stats does vary
 Paramdoes not vary

Application/Identification
Types of Statistics (2)
 Descriptive Statistic
 Stat procedures used to describe a sample
 Ex: Mean, St Devi
 Inferential Statistic
 Statistic procedure used to make decisions about a population based upon result from a sample
 Ex: TScore, ANOVA, ZScore

Application/Identification
Variables
IV, DV, EV
 Indepentdent VariablesOne manipulated by researcher
 Dependent VariablesChanges observed
 Extraneous Varibles something that effects the experiment

