topic 4 Flashcards
categorical variabes are in different categories and not continuous
true
categorical variable is often called an ordinal variable
true
binary variable has
2 categories
π is the parameter measured in terms of the proportion of people posessing the attribute
true
1-π is
the proportion not possessing the attribute
for binary variables SE is considered instead of SD
true
√[π(1-π)/n] is the
SE of binary data
binary analogue of unpaired T test
chi 2 test
compares observed and expected 2x2 tables
true
chi 2 test is done on frequencies and not percentages
true
fishers exact test is used when
there is a count of lesser than 5 in any of the cells in the table
degree of freedom in a chi2 is calcuated as
df=(r−1)×(c−1)
what is cohens kappa
it calculates the agreement or consistency between two raters or judges when they are evaluating the same terms
Cohen’s kappa is calculated as
k= p(obs) - p(exp)/1-p(exp)
value of kapa varies from -1 to 1
true
a kappa of 1, 0 and -1 indicates
perfect agreement, no agreement and disagreement respectively
need to use natural logs for log or
true
odds ratio
comparing the ratio of odds of one event to another
odds ratio of =1, >1, <1 means
odds same in each grp, odds higher in exposed grp, odds lower in exposed grp
odds ratio is particularly suited for a binary outcome with a binary predictor(exposure)
true
