Behavioral Flashcards
Triple blinded means:
Additional blinding of researchers analyzing the data.
What is the purpose of a phase I clinical trial?
Is it safe - toxicity, safety
Small number of healthy volunteers
Phase II clinical trial:
Does it work.
Small number of patients with disease.
Phase III
Large number of patients randomly assigned to treatment under investigation or best treatment available.
Is it as good or better?
Phase IV
Post marketing surveillance trial of patients AFTER approval.
Can it stay?
Detects rare or long-term adverse effects.
What is specificity?
What does specificity do in terms of ruling in and ruling out?
Specificity is
TN/(TN + FP)
Specificity - SP-P-IN - highly specific testosterone when positive rules in.
What value varies directly with disease prevalence?
PPV - Positive predictive value.
How can you calculate prevalence from incidence rate?
Prevalence = incidence rate x average disease duration
How do you calculate the odds ratio?
Odds group with disease exposed / odds group without disease exposed.
Typically used in case-control studies. “Control the odds”.
Relative Risk Reduction:
1-RR.
“Risky cohort”
Relative risk - cohort study
What is attributable risk?
It is the difference in risk between exposed and unexposed. It also is the proportion of disease occurrences attributable to that exposure.
A/a+b - C/c+d
Attributable risk percent = 100 x [(Risk in exposed - Risk in Unexposed)/(Risk in exposed)]
Number need to treat
1/ARR
Number needed to harm
1/AR
What is precision?
Precision is the consistency and reproducibility of a test. Reliability. Random error reduces precision.
What is the standard error of then mean?
It is an estimate of how much variability exists between the sample mean and the true population mean.
SEM = standard deviation/sqrt(n). N is the sample size.
In a positively skewed data set, what pattern is USUALLY observed:
Mean > median > mode
Increase power when:
Increase sample size, increase effect size, or increase precision of measurement.
If the confidence interval crosses or includes __ for 2 variables, then null hypothesis cannot be rejected. If the confidence interval crosses ____ for relative risk or odds ratio, then the null hypothesis cannot be rejected.
For 2 variables if it crosses 0. For relative risk or odds ratio if it crosses 1.
How is confidence interval calculated?
It is calculated: as the range from mean - Z (SEM) to mean + Z(SEM)
95%CI - 1.96
99%CI - 2.58
T-test is for ___.
For 3 or more groups, use _____
T-test is for 2.
ANOVA is for 3 or more groups.
The coefficient of determination is equal to
r^2 and is usually what is reported.
Disease prevention: Primary Secondary Tertiary Quaternary
Prevent - vaccination
Screen - Pap smear
Treat
Quaternary - ID patients at risk of unnecessary treatment.
Apgar scores and management
Apgar - appearance, pulse, grimace, activity, respiration
Apgar - 7 or more - healthy
Apgar 4-6 - assist and stimulate
Apgar less than 4, resuscitate.