Biostatistics II Flashcards
null hypothesis (H0)
the hypothesis to be tested (usually of “no difference”, “no effect”, or “no association between a risk factor and disease”)
alternative hypothesis (H1)
the hypothesis that contradicts the null hypothesis (usually the research hypothesis of interest)
two sided (alternative hypothesis)
Used when we are interested in any deviation from the null hypothesis (used more often than one-sided)
one sided (alternative hypothesis)
Used when we have prior evidence that leads us to be interested in a deviation from the null hypothesis in one direction
significance level (alpha)
objective cutpoint between H0 and H1. =0.05 implies 5% error
p-value
Probability of obtaining the observed sample estimate (or a more extreme estimate) by chance alone if the null hypothesis is true. The p-value is not the probability the H0 is true (a common error)
how do you calculate paired t-test
t=d/SEd (d=mean of the differences and SEd= standard error of differences)
how do you calculate 2 sample independent t-test (aka student’s test)
what is used via t-test to compare more than two groups?
ANOVA (ANalysis Of VArience)
Statistical test used is F-test
what is the equation for computing confidence intervals for proportions?
how is a 2x2 table drawn?
what is the chi-square test statistic
when is t-test used?
compare a continuous outcome variable between groups
when is chi-squared test used?
to compare a categorical outcome variable between groups
