Midterm

Question 1

p-value

Answer 1

is the probability of obtaining a result as or more extreme (more imbalance) than you did by chance. P-value tells you if the observed result can be explained by chance.

Question 2

Relative risk

Answer 2

P1/P2 used ONLY in cohort studies.The relative risk tells you the magnitude of the disease-exposure association. A big relative risk does not necessarily mean that the p-value is small.

Question 3

p-value depends

Answer 3

both on the magnitude of the relaitve risk as well as the sample size.

Question 4

Relative Risk Interpretation

Answer 4

OC users are nearly 5 times more likely to have circulatory disease than non-users.

Question 5

Relative Risk CI

Answer 5

If the 95% CI for the relative risk (RR) does not include 1 then you would reject the null which is RR=1 adn that there is evidence of a disease-exposure evidence.

Question 6

Odds Ratio can be done in which study

Answer 6

case-control or cohort studies.

Question 7

Odds Ratio Confidence Interval

Answer 7

CI intervalsl can be calculated. If the 96% condifence interal for the odds ratio does not include 1, it suggests that there is a significant association.

Question 8

P-VALUE

Answer 8

A P value that is very small indicates that the observed effect is very unlikely to have arisen purely by chance, and therefore provides evidence against the null hypothesis. P values less than 0.05 are often reported as “statistically significant”, and interpreted as being small enough to justify rejection of the null hypothesis.

Question 9

Sensitivity

Answer 9

Proportions of those with disease who are postive on the new diagnostic test.

Question 10

Specificity

Answer 10

Proportions of those with out disease who are negative

Question 11

Positve predictive value

Answer 11

The propotion of all individuals w/ a postive test who actually have disease.

Question 12

Negative Predictive Value

Answer 12

The proportion of all individuals w/ a negative test who do not have the disease.

Question 13

Simple Linear Regression

Answer 13

Y is the dependent variable.
X is the independent variable –>Predictor, Regressor, Covariate. The linear regresssion line minimizes the sum of squares of vertical deviations.

Question 14

R2

Answer 14

is a measure of association, it represents the percent of the variance in the values of y that can be explained by nowing the value of x. between 0-1

Question 15

R or the correlation coefficient

Answer 15

is a measure of the degree of linear relationship between two varaibles, usually labeled X & Y.

Question 16

Slope

Answer 16

b i sthe expected change in y per unit increase in X. Larger slopes does not necessarliy mean stronger linear association.

Question 17

Limitation of R2

Answer 17

Measuring only linear relationships, senstitive to outliers. Correlation is not causation.