Statistics
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Excel Lab 3
If you attend Open Tutorial session on Friday, March 17, then submit to Ruisi.
Otherwise, submit a printed document in class by 4.40 pm, Thursday, March 16.
You may work on this lab in groups. However, final work you submit should be your own.
Answer all questions to the best of your ability. Don’t forget to remove line spaces so
that they fit well into pages and save papers.
Problem 1
Quality Associates, Inc., a consulting firm, advises its clients about sampling and
statistical procedures that can be used to control their manufacturing processes.
Quality Associates then suggested that random samples of size 30 be taken to monitor
the process on an ongoing basis. By analyzing the new samples, the client could quickly
learn whether the process was operating satisfactorily. When the process was not
operating satisfactorily, corrective action could be taken to eliminate the problem.
The design specification indicated the mean for the process should be 12.
The hypothesis test suggested by Quality Associates follows:
H 41 = 12
H1:u ah 12
Corrective action will be taken when (and only when) Ho is rejected.
(a) Copy and paste your output from Excel.
(b) Report the correct p-value for this test here. (Be careful to look at whether you are
doing a one or two tailed test.)
(c) Based on your p-value and significance level (‘1 = 0-01), write your decision of either
reject or do not reject Ho.
(d) Write your conclusion if you can say that the mean for the process is different from
12 or you cannot say so.
(e) Then determine if any corrective action should be taken.
(f) Describe the type I error and its consequences in this hypothesis test.
Problem 2
The Battery Excel file in D2L/ Course Content/ Lab 3 shows the results of two random
samples that measured the average number of minutes per charge for AA Lithium-ion (Li-
ion) rechargeable batteries versus Nickel-Metal Hydride (NiMH) rechargeable batteries.
We want to perform a hypothesis test using CC = 0.1 to determine if the average number
of minutes per charge differs between these two battery types. Assume the population
variances for the number of minutes per charge are equal.
(a) Copy and paste your output from Excel.
(b) Report the test statistics here.
(c) Report the correct p-value for this test here. (Be careful to look at whether you are
doing a one or two tailed test.)
(d) Based on your p-value and significance level (a), write your decision of either reject or
do not reject Ho.
(e) Write your conclusion if you can say that the average number of minutes per charge
differs between these two battery types or you cannot say so.
(f) We have used the (1:0.1 significance level, which would generally be regarded as quite
small. Ifthe significance level is decreased to 0.05, then would your conclusion in (e)
will be same or different? If different write your new conclusion. (note that, p-value
does not change as significance level is changed)
