Modules 3-4 and 5-8: Descriptive and Comparative Statistics Flashcards
Identify the inferential statistical test:
2 or more groups;
independent measures;
comparing means;
normally distributed
Independent-measures ANOVA (or ANOVA)
Identify the inferential statistical test:
2 or more groups;
independent measures;
ordinal data;
NOT normally distributed
Kruskal-Wallis test
Identify the inferential statistical test:
2 or more groups;
Nominal data w/categories;
Given proportion in each category
Chi-square test
Identify the inferential statistical test needed to be used:
“There is no relationship between gender and willingness to use mental health services.”
Chi-square test
(2+ groups - male/female;
nominal data w/categories;
given proportion in each category)
Identify the inferential statistical test needed to be used:
“There is no difference in the subject’s attitude about the medical intervention, as measured by in-house survey, before and after the intervention.”
Repeated measures t-test
Is this a significant result?
t(8) = 6.00, p<0.01
E. F(3,12) = 24. 88, p<0.01, r^2 = 0.862
yes
Is this a significant result?
t(18) = 4.00, p = 0.8
no
Is this a significant result?
t(18) = 4.00, p<0.001,
95 CI [3.798, 12.202]
yes
Is this a significant result?
F(3,16) = 8.33, p<0.05, r^2 = 0.61
yes
Is this a significant result?
F(3,12) = 24. 88, p<0.01, r^2 = 0.862
yes
Does an r of 0.42 indicate a weak, moderate, or strong correlation?
Moderate (0.5-0.3)
What is “sensitivity”?
The ability of a test to identify correctly who have the disease (the proportion of diseased patients who are correctly identified as positive).
What is “specificity”?
The ability of a test to identify who does not have the disease - the proportion of diseased patients who are correctly identified as negative.
What is a positive predictive value?
tells the probability that a patient has the disease
What is a negative predictive value?
tells the probability that a patient does not have the disease
What are problems with false positives?
- Further testing increases healthcare costs;
- patient anxiety;
- diagnostic results follow patients
What are problems with false negatives?
Patient w/disease may need treatment quickly but will not receive it if the test is negative
Why are tests with high specificity important?
To rule out disease - especially if course of therapy is intensive or expensive, and requires an operation later.
How is the likelihood ratio calculated?
First - need to know pre and post test odds.
Odds = Probability/(1-probability) LR = post-test odds/pre-test odds
How is sensitivity calculated (if given odds, and specificity)?
LR+ = Post-test odds/pre-test odds LR+ = Sensitivity/(1-specificity)
Name the statistical test:
Non-parametric distribution; continuous outcome
Categorical independent variable (1)
Independent measurements
Mann Whitney Rank Sum
Name the statistical test:
Parametric distribution; continuous outcome
Categorical independent variable (1)
Independent measurements
t-test
Name the statistical test:
Non-parametric distribution; continuous outcome
Categorical independent variable (1)
NO independent measurements - matched cases or before/after testing
Wilcoxon Signed Rank
What is the non-parametric counterpart to the Chi-square test?
Fisher exact: categorical outcome, categorical independent variable (1), independent measurements
