session 6 13.1

 

Complete Session 6 Cast Study: Case Study 13.1 in the textbook.

Submit a Word document formatted in APA style complete with cover and reference pages.  The reference page must have at least one entry:  the textbook. 

The submission must be a form Research Report with the following parts:

Background information about the case:  The section must provide information about the people, places, operations, business, etc. and the research question or practical business challenges for which the current research will be used to provide a solution .  This section need not be long; up to two well written paragraphs are usually sufficient. 

Descriptive Statistics and Data illustration:  In this section, the submission must summarize how the data was obtained (see chapter 1 of the text). Graphs and charts illustrating the main features of the data are also required – please see chapter 2 of the textbook.   Finally, a table of descriptive statistics accompanied by  description and explanations of the main features of the data are also required.

Statistical Method:  This part of the submission must explain the main statistical method(s) used in the case.   What is the theory behind it? What are the working hypotheses (null and alternative, etc.), what main measures, statistics, or parameters etc.,  are to be estimated or calculated using the method; how does it measures or calculates these measures, statistics, or parameters?  Finally, this section must describe how the results of the statistical method are interpreted. That is, what is it about the results that would indicate that the working hypotheses or research questions are confirmed or rejected or perhaps need to be modified and tested again? 

Results:  The actual results of the statistical method applied to the data are now presented in this section.  The section requires the student to describe the results and their theoretical interpretation based on the description of the method described in the previous section.

Conclusion and Recommendation:  This section restates the statistical results and applies it to the business situation in the case.  It also makes practical recommendations about what steps the business in the case can take going forward based on the results of the statistical analysis.  The application and recommendation can take one or more of these general forms.

The statistical results of the data analysis provided an answer(s) to the issues that the business is facing.  As a result specific policies or practical steps can be implemented in the business. 
 The statistical results of the data analysis provided only partial answers.  More research and tests need to be done to come up with a more useful answers for the business situation.
The statistical results did not provide any useful information for the challenges that a business(s) is facing.  Recommendations for conducting new research with new approaches, data, variables, etc. may be required. 

Note

:  there is always room for ‘further research’ since it is impossible for a single research case to answer every possible question. 

Note

1. The textbook provides narratives, questions, or actual steps/questions for each case study.  While these are useful for conducting actual research, the submission must take the form of a research report and follow the above pattern.
2. Consistent with the emphasis of this course on interpretation, an edited version of the answer key for the case study have been provided here Download here.  Students are required to use the information to enhance their understanding of the statistical methods and the results obtained.  

13.1: American Oil Company

The problem Chad faces is whether a particular component part has an average diameter that meets the company’s needs. The supplier of the part states that the diameter is normally distributed with a mean of 0.16 inches and a standard deviation of 0.02 inches. Chad needs to determine whether the supplier’s claim is valid or not.

The supplier has sent Chad the following information for 330 randomly selected components.

	Diameter (inches)															Observed
	Under 0.14		5
	0.14 and under 0.15		70
	0.15 and under 0.16		90
	0.16 and under 0.17		10 5
	0.17 and under 0.18		50
	Over 0.18		10
	Total			330

Chad can use a chi-square test to determine if the component supplier’s claim is true. He would first need to determine the relevant probabilities for a normally distributed random variable having a mean of 0.16 and a standard deviation of 0.02. Using these probabilities, Chad can then determine the expected frequency of component parts that he would expect to see in a sample of 330 if the supplier’s claim is true. The observed and expected frequencies can then be used to calculate a chi-square test statistic that can be compared to a critical chi-square value. Chad’s computations are shown below.

Diameter (inches)

Observed

Under 0.14

5

0.14 and under 0.15

70

0.15 and under 0.16

90

0.16 and under 0.17

105

0.17 and under 0.18

50

Over 0.18

10

Total

330

330

Probability	Expected	(O-E)2/E
0.15865526	52.35623572	42.83373
0.149882273	49.46115005	0.00587
1.00000

The calculated value of the chi-square test statistic is ___________. The critical value for 5 degrees of freedom and a value of alpha = 0.01 is _________. Since the calculated value is __________ than the _______________ value, Chad should __________ the null hypothesis and conclude that the manufacturer’s statement that the diameter of the component part is normally distributed with a mean of 0.16 inches and a standard deviation of 0.02 inches is ____________________(true or not true). In other words, the diameter of the component part is (or is not) normally distributed with the population mean and standard deviation parameters specified by the supplier.

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