readings Flashcards
what does a regression model describes>
a relationship between the outcome variable and one or more risk factors.
is the outcome variable in re. model categorical?
no, it is continuous. ( just as in correlation).
how is the risk factor also called?
covariate/ or independent variable
how is the outcome called?
response or dependent variablee
How do you quantified the strength of the linear association?
by the correlation coefficient.
Do you need a hypotheses for multiple regression?
yes, same as correlation. `
can you predict with multiple regression?
yes, you design an equation and try to predict with it.
What does beta represent in multiple regression?
amount of change in x for y.
what happens if the CI includes zero?
the covariate is not significant.
What is a residual?
is the difference between observed outcome and model predicted outcome.
what is the beta coefficient when the variable is binary?
The beta coefficient is the difference between the mean outcome for non-baseline and baseline category, that is, b = mean of exposed – mean of unexposed.
what are noise variables?
Variables that do not have significant association with the outcome variable.
what does chi sauared do?
ompares two categorical variables to see if the variation in data is due to chance, or due to the variables being tested
ommonly used to compare the data of observed frequencies with what we would expect to occur if the null hypothesis was true.
when do you use a non parametric tst?
when data is not continuous and the normality assumption is violated,
They compare medians rather than means, as a result, if the data has outliers, their influence is negated.
what is type 1 error?
Reject the null hypothesis when in reality the null is true
