Exam 2 Flashcards
What is Bonferroni’s Adjustment used for?
- Used to correct and adjust the alpha level when multiple dependent variables are adjusted.
- Adjust alpha when multiple t tests are performed with ratio data on multiple dependent variables
What 3 things will an ANOVA measure?
1) What the effect of variable A, independent of variable B
2) What the effect of variable B, independent of variable A
3) What the joint effect or interaction of variables A and B
What is 1 thing that ANOVA will not measure?
1)What the relationship is between variables A and B
How are multifactorial designs notated? Give an example.
- Listed as how many levels of each variables time each other
- Example 3x4x5:the first would have 3 variables, second would have 4 variables, third would have 5 variables.
Which type of statistics are best used with parametric data?
interval and ratio (better than nominal and ordinal)
Which type of statistics are best used with nonparametric data?
nominal and ordinal
When would you use an independent t-test?
Two different groups with one dependent variable would use an independent t-test
When would you use a dependent t-test?
Same group or repeated measure with one dependent variable would use a dependent t-test
True/False: t-test assumes a normal subject distribution
True
With what kind of data is a t-test used for?
Ratio and interval
What is a repeated measure design?
Subjects in repeated measure studies are the same subjects thus each subject acts as their own control
What is a between subjects design?
Between subjects studies use different subjects in each group
What are 3 things that you cannot assume from a between subjects design?
1) It does not infer that all subjects were tested under all treatment conditions
2) Or that multiple comparison tests were conducted following data analysis
3) Or how the subjects in the study were assigned to the groups
What are the 3 types of ANOVAs that are used for nonparametric data?
1) Friedman Two way ANOVA
2) Kruskal-Wwallis One Way ANOVA
3) Repeated measures ANOVA
When do you use a Friedman Two Way ANOVA?
multiple groups (more than two) with nominal or ordinal data
When do you use a Kruskal-Wallis One way ANOVA?
two groups one dependent variable, nominal or ordinal data
When do you use a repeated measures ANOVA?
same subjects with different variables, nominal or ordinal data
What is a one way ANOVA?
the one way ANOVA measures the significant effect of one independent variable
What is a two way ANOVA?
The two way ANOVA is used when there are more than one independent variable and multiple observations for each independent variable.
-It can not only determine the main effect of contributions of each independent variable but also identifies if there is a significant interaction effect between the independent variables
What is the most important result to interpret from a linear regression?
r2 or R2
What does r2 represent?
The percentage of total variance determined for that variable by the predictor variables
What is the Pearson-Product Correlation Coefficient (PPCC)?
- Can assess two ratings or raters when determining reliability
- Correlation between two variables to determine their linear relationship
How is a Pearson-Product Correlation Coefficient (PPCC) reported? What does 1, -1 and 0 mean?
-Reported a number between 1 and -1. The closer to the 1 the stronger the positive relationship, the closer to -1 the stronger the negative relationship, 0 represents no relationship
What does a correlation coefficient determine?
Strength of the relationship and tells you if it is positive or negative
What does a .25, .5 and .75 correlation coefficient equate to in regards to the strength of the relationship?
.25-weak
.5-moderate
.75-strong
What is 1 thing that the t-test will answer?
1) if there is a difference between variable A and B
What are 3 things that the t-test will not answer?
1) If variable A can predict variable B
2) If there is a relationship between variables A and B
3) Or what is the joint effect or interaction of variables A and B is
What is the most important thing to look at for the interpretation of a correlation?
r value
Which type of ANOVA is best to use for nonparametric test when comparing three independent groups on one dependent variable?
Kruskal Walis One-Way ANOVA
What type of data can the nonparametric ANOVA tests be used with?
mostly nominal and ordinal data
NOTE: possible for ratio and interval. You can use nonparametric test with parametric data but the reverse is NOT true
What is the effect size characteristic?
- Based on means for quantitative data
- Can influence the magnitude of the effect of the intervention
- Can affect the estimate of the magnitude of the difference between groups
- It does not relate to the degree to which studies are similar
For between group statistics, if you are comparing 3x2x1 ANOVA with 3 comparison groups and get a p
NO. When comparing 3x2x1 ANOVA with 3 comparison groups, if the p
What is a scatter plot used for (with linear regression)?
- Visually look at data distribution and correlation
- Can see if the correlation is linear or curvilinear
- Least squares line to estimate y based on unknown x
- Can use this as a predictive value
Which coefficient correlation test would you use for parametric data?
Pearson Product-Moment Coefficient of Correlation
Which coefficient correlation test would you use for nonparametric data?
Spearman Rank Correlation Coefficient
Which coefficient correlation test would you use when both variables are dichotomous (nominal with two levels ie: gender)?
Phi Coefficient
PICTURE OF SCATTER PLOT
negative, linear correlation
-as x increased, y decreases
What is R2 in a stepwise regression?
R2 tells us how much variation within the variable there is. The larger the number the greater the variance for prediction
What is R in a stepwise regression?
R is the influence on the variable. The larger the number the greater the effect
When is the correlation coefficient stronger?
Stronger the correlation the closer to 1.0 or -1.0
What is used to predict the value of one variable on another?
Regression analysis
What is a regression analysis used for?
- Prediction of value of one variable on another is determined by doing a regression analysis
- Can determine the value of one variable based on the value of the other variable
- Prediction value cannot be safely determined if the regression line is extended past the data set (extrapolation of the line)
