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Statistics
Descriptive and Inferential Statistics
76
Mathematics
Graduate
03/08/2008

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Cards

Term
Independent Variable (IV)
Definition
Known as the predictor or causal variable
Term
Dependent Variable (DV)
Definition
Known as the criterion or outcome variable
Term

Univariate Analysis

Definition

This type of analysis is where there is one or more independent variable/s (IV) and only one dependent variable

Term
Factorial Analysis
Definition
This type of analysis is where there are two or more indpendent variables (IVs) and only one dependent variables
Term
Bivariate Analysis
Definition
This type of analysis is where there are two variables and neither are listed as the IV or DV
Term
Multivariate Statistics
Definition
This type of analysis is where there are one or more IVs and two or more DVs
Term
Mode
Definition
This measure of central tendency is best for variables measured on a nominal level.
Term
Median
Definition
This measure of central tendency is best when extreme scores are not considered and is appropriate for ordinal variables
Term
Mean
Definition
This measure of central tendency takes into account all scores in the distribution and most appropriate when variables are interval or ratio.
Term
Percentile Rank
Definition
This measure of relative position indicates the percentage of scores that fall at or below a given score
Term
Standard Score
Definition
This measure of relative position is derived from the manipulation of a raw score that expresses how far away from the mean a give score is located, usually reported in terms of standard deviation
Term
Z score
Definition
This standard score indicates the distance away from the mean score in terms of standard deviationunits and serves as a quick indicator of whether the score is located above or below the mean
Term
Spearman Rho
Definition
This measure of relationship is used if data for one or both variables are ranked (ordinal) instead of quantitative scores.
Term
Pearson r
Definition
If both variables are interval or ratio, this measure of relationship is appropriate b/c it takes into account the value of every score in both distributions.
Term
Sampling Error
Definition
Any sample will, in all likelihood, not perfectly represent the population.  This expected, chance variation among sample means is known as:
Term
Distibution of Sample Means
Definition
.  If enough samples are selected and means are calculated for each sample, all samples will not have the same mean, but those means will be normally distributed around the population mean – this is called the:
Term
Standard Error
Definition
.  The standard deviation of the sample means is usually referred to as the ________.  This tells us by how much we would expect our sample means to differ if we used other samples from the same population – and how well our sample represents the population from which it was selected – the smaller the better!  With a smaller ____________ we can have more confidence in our inferences we make about the population based on the sample data. 
Term
Null Hypothesis
Definition
States that there is no true difference to be found in the population
Term
Type I Error
Definition
If the researcher rejects the null hypothesis but is wrong
Term
Type II Error
Definition
if a null hypothesis is false but the researcher concludes that it is true
Term
Level of Significance
Definition

Also known as the Alpha level α- a pre-established (a priori) probability value of being incorrect.

(The social sciences most commonly use α = .05 → the percentage we risk being wrong.)

Term
Statistical Power
Definition
The probability of rejecting the null hypothesis when it is in fact false (a correct decision).  Like alpha, this is established arbitrarily, and should be set at a high level.
Term
Effect Size
Definition

This is the size of the treatment effect the researcher wishes to detect with respect to a given level of power. A more powerful statistical test will be able to detect a smaller ___________.  

 .2 is considered small, .5 is considered medium, and .8 is considered large.

Term
Effect Size
Definition

This takes into account things such as how many participants were involved in the research and the strength of the research (how significant they were), termed "d"

A higher ______ indicates a stronger result – means more ppl were affected      
Term
Pearson Correlation
Definition
The most commonly used bivariate correlation technique – it measures the association between 2 quantitative variables without distinction between the IV and the DV. 
Term
Bivariate (Linear) Regression
Definition

This analysis utilizes the relationship between the IV and DV to predict the score of the DV from the IV.

(1 IV and 1 DV and we’re trying to determine if the IV will predict the DV)

Term
Multiple Regression
Definition
This analysis identifies the best combination of predictors (IVs) of the DV – it’s used when there are several independent quantitative variables and 1 dependent quantitative variable.
Term
Multiple Regression
Definition
This analysis selects IVs, one at a time, by their ability to account for the most variance in the DV.  As a variable is selected and entered into the group of predictors, the relationship between the group of predictors and the DV is reassessed.
Term
Multiple Regression
Definition
2+  IVs (quantitative)                     measure of relationship/prediction

1          DV (quantitative)

 

Which analysis is this?
Term

Multiple Regression

Definition

A job promotion is the DV and our IVs are age, experience, and gender. We’re trying to find the best combination of IVs to predict the DV (promotion).

Name the analysis you would use.
Term
T Test
Definition

The most basic statistical test that measures group differences

Term
T Test
Definition

This analysis analyzes significant differences between 2 group means.        

1      IV (2 categories or levels ) i.e. yes or no   group differences      1        DV (quantitative)

Term
ANOVA
Definition
This analysis tests the significance of group differences between 2 or more group means, as it analyzes variation between and within each group.  This analysis is appropriate when the IV is defined as having 2+ categories (levels) and the DV is quantitative.
Term
ANOVA
Definition

1    IV (2+ categories/levels)             group difference    

      1    DV (quantitative)

 

Name the analysis.

Term
ANOVA
Definition

 The IV is selection methods and levels are banding, top down, and GMA test. The DV is job performance. We want to know is there are any diff amongst the three levels.

Name the analysis you would use.

Term

ANCOVA

Definition

2 or more groups are being compared on the mean of some DV, but this analysis additionally controls for a variable (covariate) that may influence the DV.

 

Name the analysis.

Term
ANCOVA
Definition

1    IV (2+ categories/levels)                group differences

1    DV (quantitative)

1+   covariate

 

Name the analysis.

Term
ANCOVA
Definition

We're looking at education and income – Does edu affect income? What about job experience? It might have an affect on what we’re looking at.

After accounting for experience there may or may not be a relationship, however at least we’ve accounted for any confounding variables or anything that could be influential.

What analysis would you use?

Term
Spurious Relationship
Definition
In ANCOVA and MANCOVA, we don't want the covariate to affect our relationship because that would then result in a ________________.
Term
MANOVA
Definition
This analysis is utilized to simultaneously study 2+ related DVs while controlling for the correlations among the DVs.
Term
MANOVA
Definition

1    IV (2+ categories/levels)                group differences

2+        DVs (quantitative)

Term
MANCOVA
Definition
This analysis investigates group differences among several DVs while also controlling for covariate(s) that may influence the DVs.
Term
MANCOVA
Definition

1 IV (2+ categories nominal or coded) → group differences

2+ DVs (quantitative)

1+ covariate

 

Name this analysis.

Term
Discriminant Analysis
Definition

This analysis is seen as the reverse of MANOVA in that it seeks to identify which combination of quantitative IVs best predicts group membership as defined by a single DV that has 2+ categories

 

 

Term
Discriminant Analysis
Definition

2+        IVs (qualitative)

1          DV (2+ categories)                  group prediction

 

Name this analysis.

Term
Factor Analysis
Definition
This analysis allows the researcher to explore underlying structures of an instrument or data set and is often used to develop and test theory.
Term
Factor Analysis
Definition
This analysis combines several related IVs into fewer, more basic underlying groups. IVs that share common variance are grouped together.  Once these groups are created, they are often adjusted (rotated) so that these groups are not highly related to one another and more accurately represent the combined IVs.
Term
Standard Error
Definition
___________ provides a direct indication of the amount of inconsistency or error to be expected in an individual’s score.
Term
Chi Square
Definition
This statistical test allows us to test for deviations of observed frequencies from expected frequencies.
Term
Variability
Definition
A measure of the degree to which the scores in a distribution are clustered together or spread apart.
Term
Degrees of Freedom
Definition
The number of scores in a sample that are free to vary with no restriction.
Term
Z Score
Definition
A standardized score with a sign that indicates direction from the mean (+/-) and a numerical value equal to the distance from the mean measured in standard deviations.
Term
Standard Error of M
Definition
The standard deviation of the distribution of sample means. The standard distance between an sample mean and the population mean
Term
Beta
Definition

_____ is also known as the probability of a Type II error.

Term
t statistic
Definition
This statistic is used to summarize sample data in situations wherre the population standard deviation is not known. This statistic uses an estimate of the standard error.
Term
Confidence Intervals
Definition
An interval estimate that is described in terms of the level (percentage) of confidence in the accuracy of the estimation.
Term
F Ratio
Definition
The test statistic used for ANOVA- compares the difference (variance) between treatments with the differences (variance) that are expected by chance.
Term
Post Hoc Tests
Definition
A test that is conducted after an ANOVA with more than two treatment condidtions where the null hypothesis was rejected. The prupose of this test is to determine eactly which treatment conditions are significantly different.
Term
Error Variability
Definition
Unexplained, unsystematic differences that are not caused by any known factor
Term
Main Effect
Definition
The overall mean differences between the levels of one factor. When the data are organized in a matrix, the __________ are the mean differences among the rows (or among the columns).
Term
Interaction
Definition
Mean differences that cannot be explained by the main effects of the two factors. An _________ exists when the effects of one factor depend on the levels of the second factor.
Term
Expected Frequencies
Definition
Hypothetical, ideal frequencies that are predicted from the null hypothesis
Term
Observed Frequencies
Definition
The actual frequencies that are found in the sample data
Term
Homoscedastic
Definition

When samples have approximately equal variances, they are said to be ________. This is an assumption of several analyses.

Term
Independent T-Test
Definition
When choosing which t-test to use, this t-test should be used when there is no correlation between the two groups
Term
Dependent T-Test
Definition
When choosing which t-test to use, you would use this t-test when two sets of data (pair of scores) from matched subjects or from the same subject (repeated measures) are correlated.
Term
t statistic
Definition
This statistic calculates mean difference/standard error.
Term
Statistical Power
Definition
By maximizing mean difference and minimizing standard error, you are increasing _______.
Term
Leptokurtic
Definition
This type of kurtosis occurs when the value is over +2, indicated a non-normal distribution.
Term
Platykurtic
Definition
This type of kurtosis occurs when the value is below -2, indicates a non-normal distribution.
Term
Practical Significance
Definition
Considers whether a statisticall significant research finding has applied value and use, can be important when deciding whether or not to act upon a research finding.
Term
Practical Significance
Definition
Traditionally _________ should explain 20% of the total variance, can be tested using several formulas, the most common is eta squared
Term
Statistical Significance
Definition
Based on a predetermined level of probability corresponding to random findings established by the researcher prior to conducting a chosen analysis, varies as a function of the discipline (Business= .10, Psychology = .05, Medical = .01) The probability corresponds to the possibility that the finding occured randomly. Thus, when the _______ is .05, the likelihood of random findings is 1 out of 20 and the likelihood of non-random findings is 19 out of 20.
Term
Effect Size, Alpha, Sample Size
Definition
Power is determined by these three factors:
Term
Multicollinearity
Definition

The degree to which variables can be predicted or accounted for by other variables in the analysis- As this increases, the ability to define a single variables' effect is diminished.

Term
Heteroscedastic
Definition
A distribution is said to be ________, when there is a skewed distribution, resulting in unequal dispersion or from sample size discrepencies
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