IBA134 Business Statistics
OUA Study Period 2 (SP2), 2013
Computer Assignment
(Worth 15% of the overall assessment for the unit)
Due date: 5pm (QLD time) on Sunday 11, August 2013
Instructions:
• All numerical calculations and graphs/plots should be done using EXCEL.
• A hard copy of your completed assignment must be submitted electronically with the Griffith OUA Cover Sheet (available in the Assessment section of the unit website) attached as the 1st page of your submission. See instruction on the IBA134 Business Statistics unit website under “Assessment” and “Online submission of assignments using SafeAssign” on the link
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(b) Use five of the above summary measures to represent the summary information in a box plot for each variable.
(c) Compute a numerical summary measure to measure the strength of the relationship between the two variables. Interpret this value.
QUESTION 4
The researcher wishes to estimate the population means for the two variables under consideration using the sample data.
(a) Compute the best point estimates for the mean of the two variables and their standard errors.
(b) Construct a 95% interval estimate for the population mean of each of the two variables.
(c) Explain what would happen to the two interval estimates in 4(b) above if we use a level confidence 90% instead of 95%. Justify your answer by re-calculating the 90% interval estimates for the population mean of the two variables.
QUESTION 5
The researcher wishes to test hypotheses about the population means for the two variables under consideration using the sample data.
(a) The researcher believes that the average television time per week is more than 25 hours. How do you test his believe? Is there any evidence for his believe? Use a 5% level of significance.
(b) The researcher believes that the average debt is less than $150,000. How do you test his
b. Construct a 91.5% confidence interval for the mean time it take for all workers who are employed in downtown Toronto
11. List the five steps of hypothesis testing, and explain the procedure and logic of each
Select one (1) project from your working or educational environment that you would use the hypothesis test technique. Next, propose the hypothesis structure (e.g., the null hypothesis, data collection process, confidence interval, test statistics, reject or not reject the decision, etc.) for the business process of the selected project. Provide a rationale for your response.
The customers in this case study have complained that the bottling company provides less than the advertised sixteen ounces of product. They need to determine if there is enough evidence to conclude the soda bottles do not contain sixteen ounces. The sample size of sodas is 30 and has a mean of 14.9. The standard deviation is found to be 0.55. With these calculations and a confidence level of 95%, the confidence interval would be 0.2. There is a 95% certainty that the true population mean falls within the range of 14.7 to 15.1.
Create a research hypothesis tested using a one-tailed test and a research hypothesis tested using a two-tailed test.
Fry Brothers heating and Air Conditioning, Inc. employs Larry Clark and George Murnen to make service calls to repair furnaces and air conditioning units in homes. Tom Fry, the owner, would like to know whether there is a difference in the mean number of service calls they make per day. Assume the population standard deviation for Larry Clark is 1.05 calls per day and 1.23 calls per day for George Murnen. A random sample of 40 days last year showed that Larry Clark made an average of
3. In testing the difference between the means of two independent populations, if neither population is normally distributed, then the sampling distribution of the
Be sure to show the data from your sample and the data to support your estimate.
This assignment requires a considerable amount of computer work and written comment. You may need to seek guidance from your tutor along the way. Do not leave things until too late. Each question carefully describes what you are required to do, so please follow these carefully.
b. The investigators, of the secondary data which I will be using, operationalized their variables by surveying 80,237 individuals across the United States and documenting their contact with the police. The data was collected between July 1, 2005, through July 31, 2005, using a stratified multistage cluster sample. A weight was used in order to obtain national estimates. In addition, the mode of data collection was
Conclusion : Reject the null hypothesis. The sample provide enough evidence to support the claim that mean is significantly different from 12 .
What is the value of the population mean? What is the best estimate of this value?
3. Sample Population: Who exactly was used in the study? How many? (Be as specific as possible.)
Hypothesis is typically used in quantitative research only. Moreover, when a question poses an inquiry on the relationship between two variables, a hypothesis is a statement declarative in nature of the relationship between different variables (Pajares 2007). A researcher chooses whether to use a question or a hypothesis depending on the purpose of the research, its objectives, the methodology for the research and the preference of the audience to receive the research. A researcher must be able to interpret the final outcome with reference to the research questions or the hypothesis used (Pajares 2007). A research requires a minimum of two hypotheses namely a null and an alternative hypothesis.