week 4 Flashcards
bias occurs if certain participants have a/an ________ probability of being selected
unequal
random sampling examples
simple random
stratefied
cluster
non-probability sampling examples
convenience sampling
quota sampling
snowball sampling
standardized normal distributeion
gaussian distribution
z score and its equation
labeled by number of standard devs
Z=(X-(MEAN OF X))/ standard dev
percentile equation
(# of scores less than x)/N x 100
inference
making generalizations about a pop based on data from samples
use hypotheses to make inferences
null hypothesis
no association
no difference in means
no difference in proportions
alternate hypothesis
there is an association
diff in means or proportions
alpha
the probably that the investigator accepts a priori that the results may be due to chance rather than a true difference
accepted proability of a type 1 error
p value
the actual probability from the data that results are due to chance rather than a true difference
the probability that a null hypothesis is true
reject the null if
p
type I error
recommend/ provide treatment that is inneffective
type II error
failure to identify an effective treatment that may benefit your patient
confidence interval
calculated range of values around the estimated measure that has a specified (95%) probability of including the true value of the measure in the population
may be used to determine significant, or precision
based on standard error
