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74 Cards in this Set
- Front
- Back
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When is one-way ANOVA used?
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-one DV
-one IV -three or more levels of the IV (Can use ANOVA with 2 levels) |
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What are the 2 sources of variance in the one-way ANOVA
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-Treatment variance
-Error variance |
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What type of size values (large or small) do we want the 2 sources of variance to be
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-Treatment variance LARGE
-Error variance small |
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How is ANOVA represented
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"F"
F= Treatment variance/Error variance the bigger the "F" value, the more likely to reject the null |
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What does ANOVA stand for
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Analysis of Variance
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What is the Error variance attributed to
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-participants
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What can affect the participants
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environment: causes participants to react diff when assessed on the DV
history: causes diff. responses to treatment |
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Equation
Degrees of Freedom for ANOVA |
F = MSbetween/MSerror
MS-mean squared MS = SS/N or SS/N-1 SS: Sum of Squares N: sample size for population N-1: sample size for sample |
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What is the difference between MSb and MSe
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with the "b", it is the number of groups (k)-1
with the "e", it is the total number of participants (N-k) |
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What are the seven steps in ANOVA
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1)State the null
2)One-way ANOVA (equation F=) Assumptions 3)alpha=0.05 4)Criteria for rejecting the null (p<0.05) 5)run the test 6)Accept/reject the null 7)Post Hoc Test 8)conclusion |
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When do you reject the null for ANOVA
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-when there are more than 2 groups only tells us that AT LEAST 2 of the groups are different
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What is the Tukey Post Hoc test
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Pairwise comparisons between means
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What is one of the most used Post Hoc tests
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Tukey
-can be used to determine which pair of means are different -controls against type 1 errors |
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After using the Post Hoc test, when do you reject the null
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if the mean difference (absolute value) is greater than or equal to the Tukey contrast value
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When are Bivariate Correlation used
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When there are two different variables that have been measured
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What would the investigator be interested in with Bivariate Correlation
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In determining if there is a relationship between the two variables
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True or False
If a relationship is found between variables, that indicates a cause and effect |
FALSE
i.e. Height and weight in adults...incr, in weight does not mean an incr. in height |
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When r=1.00 in correlation...
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Considered a perfect positive correlation or relationship between the variables
Scores high/low for both variables |
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When r=-1.00 in correlation...
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Considered a perfect negative correlation or relationship
Score high for one variable, but low for the other |
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What are used to view relationships between variables
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Scatterplots
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What is the most common type of correlation
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moderately positive/negative correlation
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What are the positive descriptors used with correlation
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r=1.00 - .80 Strong pos.
r=.80 - .40 Moderate pos. r=.40 - 0 Weak pos. |
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What are the negative descriptors used with correlation
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r=0 to -.40 Weak neg
r=-.40 to -.80 Moderate neg r=-.80 to - 1.00 strong neg |
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In what ways can correlations may be used (3)
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1.Determine the relationship between 2 variables
2.Determine the reliability of a measuring instrument 3.Determine the validity of a test |
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What is assumed with correlation techniques
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there is a linear (straight) line relationship between variables
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How is assumption with correlation techniques checked
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by drawing and looking at the line of best fit
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Correlation Techniques
Person Product Moment Correlation |
This is a parametric technique that is symbolized by a small letter "r"
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Correlation Techniques
Spearman Correlation |
This is a nonparametric technique also symbolized using "r"
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What are the assumptions for Person Product Moment Correlation
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1)one group randomly selected from the population of interest
2)both measured variables be interval/ratio data type 3)Data on each variable must be normally distributed 4)variables must have a linear relationship to each other 5)variances of the two variable must be equal |
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What is the Homoscedasticity assumption
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Assumption asks if the variances of data points are equally distanced from the line of best fit
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How do we determine if the Homoscedasticity assumption is met
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ellipse shape circles are drawn around the points to decide if assumption is met
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What is the seven step procedure for Pearson Product Moment r
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1)Write the null
2)get the Pearson Product Moment r formula 3)determine the alpha level 4)Determine the critical value (state when the Ho is rejected) 5)calculations 6)Compare calc. to critical r 7)state conclusion |
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What is the Coefficient of Determination
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=r squared
tells us the proportion of shared variance by the two variables The amount of variance explained in performance on one variable by knowing the performance on the second variable |
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What is a synonym for regression
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Prediction
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What must be done first between X and Y variables
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the Correlation
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What are soem examples of Regression
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-GRE tests predicting individual's success in grad school
-measuring skinfolds to predict body fat % -determining activity level and measuring BMI |
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What is the prediction/regression formula
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Y'=bX + a
**same formula for a straight line** where "b" is the slope and "a" is the y-intercept |
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What is the difference between Y and Y'
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Y is the actual observed score
Y' is the predicted score |
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What does the regression line describe
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formula for the line describes the line of best fit
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How many points are needed to define a line
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2
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What can be calculated by knowing 2 points in the line
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The slope (a) and the y-intercept (b)
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True or False
Estimates are made for the line of best fit using all of the data because we do not know the 2 points to begin with |
True
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what does the slope steepness depend on
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how the changes in the X variable (predictor) are related to changes in the Y variable (criterion)
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What does the regression line describe
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formula for the line describes the line of best fit
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How many points are needed to define a line
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2
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What can be calculated by knowing 2 points in the line
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The slope (a) and the y-intercept (b)
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True or False
Estimates are made for the line of best fit using all of the data because we do not know the 2 points to begin with |
True
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What does the regression line describe
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formula for the line describes the line of best fit
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what does the slope steepness depend on
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how the changes in the X variable (predictor) are related to changes in the Y variable (criterion)
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How many points are needed to define a line
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2
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What can be calculated by knowing 2 points in the line
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The slope (a) and the y-intercept (b)
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True or False
Estimates are made for the line of best fit using all of the data because we do not know the 2 points to begin with |
True
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what does the slope steepness depend on
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how the changes in the X variable (predictor) are related to changes in the Y variable (criterion)
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How is the line of best fit drawn
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1)Place dot where the mean X score meats the mean Y score
2)locate the y-intercept value 3)connect the two points |
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True or false
Using the scatterplot and prediction line is a precise way of predicting |
False
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True or false
Once prediction formula is developed, it is use on individuals who were involved in its formulation |
False
Individuals who were NOT involved |
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What are the X values for each individual entered into
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The prediction formula to determine a predicted Y score
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What is the minumum number of sujects needed per variable
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40
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Why is there a minumum requirement of suject with regression lines
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half of the subjects are used to develope the regression prediction formula and the other half are used to test the formula
-need to determine if it is a good prediction formula |
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When are predicitons considered to have NO errors
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when r = 1.00 or -1.00
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What is error of estimates
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residual
the actual Y value minus the predicted Y value |
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Definition
Variance error of estimate |
The variance of a sample of residuals
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Definition
Standard Error of Estimate (SEE) |
The square root of variance error of the estimate
also-the standard deviation of the residuals |
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True or False
Want the standard error of estimate to small |
True
The smaller it is, the more precise the prediction |
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What will result in a smaller SEE (standard error of estimate)
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small stnd dev for the Y scores and high magnitude for r
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Formula
SEE |
= sy x (sq rt. of 1-r squared)
sy- stnd dev of Y variable |
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What are the assumptions for Bivariate regression
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Same as correlation
1)Randomness 2)normal distribution 3)linear relationship btwn IV and DV |
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What is multiple Regression
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has more than on IV
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What is the general purpose for multiple regression
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asses relationship between one variable (DV, symbolized as y) and several others (IVs, predictor, or x)
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What can the IV be for multiple regression
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-Correlated or not
-Continuous or categorical -Naturally occurring or manipulated |
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What is the formula with multivariate regression
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Yp=a + b1X1 + b2X2 +.....
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Definition
Beta Weights |
The standardized regression coefficients (b in the equation)
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What are Beta Weights used to determine
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the importance of the IV in relation to the DV
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True or false
Beta Weights are really the raw regression coefficient (raw score) converted to a z-score |
True
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