Inferential Statistics Flashcards
(30 cards)
when does sampling error occur
when the sample does not accurately reflect the pop
2 purposes of inferential stats
1- estimate pop parameters from sample data and to test hypothesis
2- hypothesis are tested in nursing research studies
def central limit theorem
phenomenon in which sample values tend to be normally distributed around the pop value
def sampling distribution
a theoretical freq distribution based on an infinite number of samples
def standard error of the mean
the standard deviation of the sampling distribution of the mean
def confidence interval
a range of values that, with a specified degree of probability, is thought to contain the population value
def level of significance
the probability of rejecting a null hypoth when it is true, and it should not be rejected
def one tailed test of significance
differences or correlations are sought in only one tail of hte theoretical sampling distribution
def two tailed test of significance
used to determine sigificant values in both ends of the sampling distributions
non directional hypoth
def type i error
if the null hypoth is actually true an you reject it
def type ii error
if the null hypoth is actually false and you fail to reject it
t/f- as the probability of type i error incr, prob of type ii decr
true
what is the most likely reason for type i errors
unnecessary changes being instituted
what is the most likely reason for type ii errors
failure to institute needed changes
def parametric tests
concerned with pop parameters and these tests make assumptions abt a pop from a sample
def non parametric tests
less stringent in the requirements for their use and do not make assumptions abt the pop from a sample
assumptions of the parametric test
1- level of measurement of data is interval or ratio
2- data are taken from pops that are normally distributed on the variable being measured
3- data are taken from pops that have equal variances on the variable being measured
def power of a statistical test
the ability of the test to reject a null hypo when it is false
3 most common stat tests
t test
analysis of variance
chi square
def t test
a parametric tess that examines the difference bx the neab values if some variable in 2 groups
- degrees of freedom
def dependant t test
aka paired t test or correlated t test
used when scores or values are assoc or have some connection
def analysis of variance (ANOVA)
compare the differences among more than 2 means
researcher is able analyze the difference bx several means at one time
def chi square test
a non parametric inferential technique appropriate for comparing sets of data that are in the form of frequencies or percentages
used most commonly with nominal data
def multiple regression
procedure used when the researcher wishes to determine the inlfuence of more than one independant variable on the dependant variable
