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Flashcards in week 6 Deck (14)
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1

ratio

division of 2 frequencies
one quantity not a subset of the other

2

event rate/risk

probability that the even will occur

3

proportion

freq in one group / total

4

chi square tests

data are categorical
numbers are frequencies
mutually exclusive and exhaustive
2 types

goodness of fit: tests observed proportions against a known proportion

test of independence: tests for an association between the 2 variables

need a p value to determine if there is an association or not

5

relative risk

how many times more or less likely a person exposed to a condition develops the condition compared to an unexposed person

RR=(incidence of outcome with exposure)/(incidence of oucome without exposure)

if RR=1, not likely
if RR>1 more likely in exposed
if RR

6

odds ratio

how many more times likely the odds of finding an exposure in someone with a disease is compared to finding an exposure in someone without the disease

OR=(odds of exposure in those with disease)/(odds of exposure without disease)

7

confidence intervals

range of possible values around the point estimate

95% probability that the true value falls within the interval

width determines precision

may be used for significance (if 1 in included in RR interval, not significant)

8

confounder

a third variable that influences the exposure/treatment-outcome relationship

9

multivariate analysis in experimental research

adjustment for confounding is needed when randomization isnt successful

10

multivariate analysis in observational research

adjustment for confounding is needed because its not randomized

11

linear regression

used for prediction of an outcome based on an independent variable

best fit lines

numeric variables

12

logistic regression

used for dichotomous outcomes

13

r squared value

indicated how much variability in y is explained by the model

14

association vs effect

association implies a mere statistical relationship

effect implies that the relationship is causal