Hypothesis Testing
Prof. Myllah D. Garcia

Test for a Mean
Many hypotheses are tested using a statistical
test based on the following general formula:
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Observed value is the statistic (mean) that is
computed from the sample data
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Expected value is the parameter (mean) that
one would expect to obtain if the null
hypothesis were true â€“ hypothesized value.
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Standard error of the statistic being tested.

Steps for Solving Hypothesis-
testing Problems
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Step 1:
State the hypothesis and
identify the claim.
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Step 2:
Find the critical value(s).
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Step 3:
Compute the test value.
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Step 4:
Make the decision to reject
or not reject the null hypothesis.
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Step 5:
Summarize the results.

Z Test for a Mean
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The z test is a statistical test for the
mean of a population.
It can be used
when
or when the population is normally
distributed and
is known.

Example 1
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A researcher reports that the
average monthly salary of nurses is
more than 35,000 pesos.
A sample
of 35 nurses has a mean of 36,375
pesos.
At
, test the claim that
nurses earn more than 35,000 pesos
a month.
The standard deviation of
the population is 5,900 pesos.

Example 1

Example 2
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A researcher reports that the average cost of
rehabilitation for stroke victims is 100,000 pesos.
To see if the average cost of rehabilitation is
different at a particular hospital, a researcher
selects a random sample of 40 stroke victims at
the hospital and finds that the average cost of
their rehabilitation is 115,000.
the standard
deviation of the population is 42,000 pesos.
At ,
can it be concluded that the average cost of
stroke rehabilitation at a particular hospital is
different form 100,000 pesos?

Example 2

P-value Method for
Hypothesis Testing
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P-value (or probability value) is the
probability of getting a sample
statistic (such as the mean) or a
more extreme sample statistic in the
direction of the alternative
hypothesis when the null hypothesis
is true.

Solving Hypothesis-testing
Problems (P-value method)
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Step 1: