Biostats Flashcards
Sensitivity =
Sensitivity = TP/(TP+FN)
Specificity =
Specificity = TN/(TN+FP)
The greater the prevalence of a disease, the greater the ___?
PPV
The lesser the prevalence of a disease, the greater the ___?
NPV
The lesser the prevalence of a disease, the greater the ___?
NPV
What is the absolute risk reduction conceptually?
Percentage decrease in the risk of disease/death from a treatment compared with the total number of people in a population
What percent is 1 SD?
68%
What percent is 2 SD?
95%
What percent is 3 SD?
99.7%
What is the Mode?
The most frequently appearing value
What is the incidence?
New numbers of cases per unit time
What is the prevalence?
Total number of cases in a population
What does the T-test measure?
2 groups of data
What does the ANOVA test measure?
3+ groups of data
What does the Chi-Square test measure?
Multiple categories of groups, asks if the groups are related or not
Which type of study involves samples sorted into different arms randomly?
Randomized Controlled Trial
Which type of study involves observing prospectively over time what happens to groups of patients with a certain exposure or illness?
Cohort Study
“Teens are a risky cohort”
Which type of study retrospectively views data looking for the odds of a previous exposure on the development of a rare disease?
Case Control Study
“That was an odd case”
Which type of study bias uses hospitalized patients instead of general population?
Berkson bias
Which type of study bias occurs when the study subjects know they are being watched?
Hawthorne Effect
What is a Type I error?
Rejecting the null when it really is true– eg: saying the new drug works when it really doesn’t
What is a Type II error?
Saying the drug does not work when really it does
