chapter 5: Challenges in Statistics Flashcards
(45 cards)
what type of study can we see prevalence used in?
cross sectional
define prevalence
fraction of the group that has the disease AT ONE single point in time
define incidence
rate of NEW cases of disease over a PERIOD of time
a test that compares the observed vs expected numbers of subjects in each category is known as
chi-square goodness of fit test
what is the best test to do for counts/frequency of things occurring within a sample
chi square goodness of fit test
what does it mean when the p value is low in a chi square test
reject the null that things are due by chance/random not related to what was expected
aka something really is going on.. (observed results are different from expected)
some factor other than chance must account for the large number of deaths from CHD while fighting fires
what does it mean when the p value is high in a chi square test
do not reject the null hypothesis that there really is no true difference b/w observed and expected and it is due by chance/random.
in a chi square test what is the null hypothesis in the data
the number expected
t/f cross sectional study can determine incidence
false! incidence are cases over a PERIOD of time vs cross sectional study is in a single point in time
cross sectional are divided into groups based off of _____
risk factors
single samplle of subjects is selected without regard to either the disease or the risk factor test is known as
cross sectional study
the prevalence of disease is compared between two groups can be tested with
cross sectional test
what type of study is a longitudinal study
propetive study
what type of study is one that collectsdata NOW and continues later
prospective study
what study observes over time to determine the incidence rates in the two groups selected
prospective study
what type of study has a single sample of subjects selected and randomly divided into two groups where outcomes or incidence is observed
expermental study
which study is easier to do and why, retrospective or prospective
retrospective; its using data that has already been collected! all you need to do is interpret the results
is a case control study retrospective or prospective and how
retrospective bc looking at risk factors that some people already have i.e. smokers (already smoke; not telling them to start smoking for the purpose of the study)
what does randomized study mean
so you already have the group that youre going to be studying on and THEn randomize them into groups like one will receive the medication and another the placebo
single blind vs double blind study
single: the patient doesnt know what theyre getting
double: the patient NOR the person conducting study (researcher) knows what group the patients are in
if the Confidence interval does not have a range of zero; i can assume that this test result is ____
statistically significant
i.e. the null hypothesis is saying that there is NO difference aka the difference would equal to zero; so if there is a zero in the CI range, this means that the null hypothesis is not rejected and the result is NOT statistically significant
if the Confidence interval does not have a range of zero; i can assume that this test result is ____
statistically significant
i.e. the null hypothesis is saying that there is NO difference aka the difference would equal to zero; so if there is a zero in the CI range, this means that the null hypothesis is not rejected and the result is NOT statistically significant
how can we tell if a study is stat significant without a pp value ?
The CI range, if there is NO zero in the range we can say it is stat significant
the incidence of disease attributed to the risk factor minus the incidence of the disease in persons not exposed to the risk factor is known as
attributable risk
