HLT-362V-Applied Statistics for Health Care Professionals Quiz 2.
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Applied Statistics Quiz 2
Math Statistics Hypothesis Testing
Terms in this set (8)
What research decisions
influence the magnitude of
Type I error?
The nominal alpha level sets the limit on the
magnitude of risk of Type I error. The risk of
committing the error is the alpha level.
Example: alpha level = .05, the risk of committing
error is 5%.
How are risk of Type II error
and statistical power related?
Risk of Type II error is beta and statistical power is
(1-beta). So, as risk of Type II error increases,
statistical power decreases.
Other factors being equal,
which type of significance test
requires the value of t that is
larger (in absolute value) in
order to reject HO: a
directional or non-directional
test?
A non-directional test or two-tailed test requires a
value of t that is larger in absolute value to reject
HO compared to a directional test.
What is a null hypothesis? What
is an alternative hypothesis?
A null hypothesis states one specific value for the
unknown population mean m. An alternative or
research hypothesis states a range of
outcomes/values for the population mean m. Also,
Applied Statistics Quiz 2 the alternative can be directional or non-directional.
What is an alpha level? What
determines the value of alpha?
Alpha level is a theoretical risk of Type I error that is
chose by the researcher prior to looking at the
results of a study. Usually it corresponds to
conventional standards for level of acceptable risk.
What is an "exact" p-value?
It is the level of marginal significance within a
statistical hypothesis test. It is used as an alternative
to rejection points to provide the smallest level of
significance at which the null hypothesis would be
rejected.
What is statistical power? What
information is needed to
decide what sample size is
required to obtain some
desired level of power (such as
80%)?
Statistical power is the likelihood that a study will
detect an effect when there is an effect to be
detected. The information needed to evaluate
statistical power is: alpha level and population
effect size. Using these values, a statistical power
table can be used to find out how sample size
corresponds to power and that can be used to
decide what minimum N should be necessary for a
level of power such as .80.
EXTRA CREDIT: When a
research reports a "p" value, p
stands for "probability" or risk.
a. What probability does this p
refer to?
b. Do we typically want p to be
large or small?
What is the conventional
standard for an "acceptably
small" p-value?
a. The theoretical risk of committing a Type I error.
b. We typically prefer p, the risk of Type I error, to
be small (usually smaller than .05)
c. The usual conventional standard is p < .05 (or
sometimes p < .01 or .001)