Your favorite professional football team (I shall refer to them as the

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STEP BY STEP Critical Value Approach to
Hypothesis Testing 1- State Ho and H1 2- Choose
level of significance, a Choose the sample
size, n 3- Determine the appropriate test
statistics and sampling distribution. 4-
Determine the critical values that divide the
rejection and non-rejection areas. 5- Collect
the sample data, organize the results and compute
the value of the test statistics. 6- Make
the statistical decision and state the managerial
conclusion If the test statistics falls into
non-rejection region, DO NOT REJECT Ho If
the test statistics falls into rejection region,
REJECT Ho The managerial conclusion is written
in the context of the real world problem.
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ACTUAL SITUATION
STATISTICAL DECISION
H0 IS FALSE
H0 IS TRUE
CORRECT DECISION 1-a TYPE II ERROR ( ß ERROR)
TYPE I ERROR (a ERROR) CORRECT DECISION 1-ß
DO NOT REJECT H0
REJECT H0
If the null hypothesis is true and accepted or
false and rejected the decision is in either case
CORRECT. If the null hypothesis is true and
rejected or false and accepted the decision is in
either case in ERROR.
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Exercise - 1 One Tailed Test TEST at the 5
level whether the single sample value of 172
comes from a normal population with mean µ 150
and variance s2100.
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Exercise McDonald One Tailed Test In one past
study, McDonalds had a mean service time of
174.22 seconds. Suppose that this company began a
quality improvement effort to reduce the service
time and selected a sample of 25 stores. The
sample mean has been calculated as 162.96 seconds
and sample standard deviation is 20.2 seconds.
You wish to determine whether the new
drive-through process has a mean that is less
than 174.22 seconds.
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Exercise Internet Access Z-test for
Proportion Of 2000 adults, 1540 said that they
wanted Internet Access so, they could check
personal e-mail while on vacation. A survey
conducted in the previous year indicated that 75
of adults wanted Internet Access. Is there
evidence that the percentage of adults who wanted
Internet Access has changed from the previous year
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Exercise 3 The manager of the womens dress
department of a department store wants to know
whether the true average number of womens
dresses sold per day is 24. If in a random sample
of 36 days the average number of dresses sold is
23 with a standard deviation of 7 dresses, Is
there, at the 0.05 level of significance,
sufficient evidence to reject the null hypothesis
that µ24?
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Exercise 4
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Exercise 5
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Exercise Wind Speed A researcher claims that
the average wind speed in a certain city 8 miles
per hour. A sample of 32 days has an average wind
speed of 8.2 miles per hour. The standard
deviation of the sample is 0.6 mile per hour. At
a 0.05, is there enough evidence to reject the
claim? Use p-value method.
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Exercise Starting Salary A job placement
director claims that the average starting salary
for nurses is 24,000 USD. A sample of 10 nurses
salaries has a mean of 23,450 USD and a standard
deviation of 400 USD. Is there enough evidence to
reject the directors claim at a0.05?
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Exercise 6
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Exercise Room Rates A survey found that the
average hotel room rate in Antalya is 88.42 TL
and the average room rate in Izmir 80.61 TL.
Assume that the data were obtained from two
samples of 50 hotels, each and that standard
deviations were 5.63TL and 4.83 TL, respectively.
At a 0.05, can it be concluded that there is
significant difference in the rates?