lecture 6 Flashcards
two types of quantitative data
continuos (all values in possible range)
discrete (only certain values possible)
two types of categorical data
nominal (in category but no order to data)
ordinal (data has specific order)
the ___ the r^2 the better the fit of the regression line
higher
type I error
rejecting the null hypothesis that is actually true
type II error
failing to reject the null hypothesis that is actually false
how to calculate power
1-B (b is type II error)
t-test
used to determine whether the mean value of a continuous outcome variable differs significantly between two independent groups
when to use one sample t-test
outcome variable of interest is only being examined in one group
matched-pair t-test
used when subjects are matched in pairs and their outcomes are compared within each matched pair
when to use chi squared
categorical data
ANOVA
uses F-statistic, allows for comparison of several population means
t/f: the p value says nothing about the clinical relevance or quality of the study
true
limits of statistical interference
only tells about role of chance/random error
does not tell you about role of bias or confounding
DOES NOT TELL U ABOUT CAUSALITY
bias
systematic error in the design, conduct or analysis of a study that results in a mistaken estimate of an exposures effect on dz
selection bias
systematic error in selecting subjects into one or more of the study groups
