Epi 3: Selecting Statistical Tests Flashcards
List 4 different categories that answer question # 2 in selecting correct statistical test.
Q2 = What type of comparison/assessment is desired?
- Correlation - 2 groups
- Regression - prediction, 3+ groups
- Survival Comparison - time
- Group Comparison
2 vs. 3+ groups;
independent vs. paired/related
“prediction” indicates which category of statistical tests
Regression
3 regression tests = Logistic Regression, Multinominal Logistic Regression, Linear Regression
What does correlation statistical test compare?
Quantitative representation of STRENGTH + DIRECTION of a relationship between TWO variables
FIXED value range = [-1 - +1]
\+/- = direction value = magnitude of strength
How many Correlation statistical tests? Are any specific to particular data level?
Contingency Coefficient (nominal) Spearman Correlation (ordinal) Pearson Correlation (interval) Kappa Statistic
For Pearson Correlation test, what does a statistically significant value (p < 0.05) and a non-statistically significant value (p > 0.05) indicate?
p < 0.05: Linear correlation is present between 2 groups
p > 0.05: NO linear correlation, but may be a non-linear relationship present!!!
Under what circumstances would you run a Pearson Correlation as a “partial correlation”? What level of data would this involve?
Partial Correlation = correlation stat. test that controls for confounding variables
Only interval data = Pearson Correlation
Contingency Coefficient
Correlation stat. test
Nominal data
Spearman Correlation
Correlation statistical test
Ordinal data
Pearson Correlation
Correlation stat. test
Interval data
Kappa Statistic
A correlation; measures STRENGTH + DIRECTION of agreement between different evaluators;
Compares ability of different evaluators to classify/interpret same data into 1 of many groups.
Ex.- 2 different radiologists interpret/classify the same radiographic image
FIXED value range: [-1 - + 1]
+/- = good agreement/poor agreement
What does a regression measure? What else can be calculated from a regression?
Measure of relationship between multiple variables (IV) specific ability to predict outcome variable (DV)
Odds ratio for measure of association + control for confounding variables
How determine the data level of a Regression?
= data level of outcome variable (DV) = variable being predicted
What type of data comparison group can calculate Odds Ratio (OR)?
regression
Nominal data + regression test =
Logistic Regression
Ordinal data + Regression test =
Multinominal Logistic Regression
Interval data + Regression test =
Linear Regression
Logistic Regression
multiple independent variables used to predict outcome/dependent variable (DV)
predicted outcome data level = nominal
Multinominal Logistic Regression
multiple independent variables used to predict outcome/dependent variable (DV)
predicted outcome data level = ordinal
Linear Regression
multiple independent variables used to predict outcome/dependent variable (DV)
predicted outcome variable data level = interval