Assignment 1

Topics: Standard deviation, Normal distribution, Mean Pages: 5 (1301 words) Published: July 1, 2012
Chapter 1.
6. Many drug safety research studies are sponsored by pharmaceutical companies that would financially benefit if the results of the study are favorable. Is this an example of a potential confounding factor?

If the sample to test is selected to favor the results of the drug company, it would be categorized as a confounding factor, but if instead the drug company is sponsoring a serious study where the sample is selected randomly and divided in treatment and control groups, the experiment will be fairly analyzed and the results will be closed to reality.

13. Below are some data from 2005 for on-the-job deaths in dangerous jobs. Which job seems the most dangerous? Which seems the least dangerous? Explain.

After calculating the percentage of employee’s deaths per total employees, Fishers and Fishing workers appears to be the most dangerous with a percentage of .12% of deaths per total employees, but instead the job that appears to be the least dangerous is Construction Laborers with a .023% of deaths per total employees. Regardless of having the government data and assume by the data the most and least dangerous jobs, I will think we need different data that shows other types of death’s variables, such as deaths cause by natural causes, aging, health issues or accidents, to make the result more realistic.

15. A recent Harvard Business Review article titled “When to sleep on it” discusses the usefulness of deliberating a business decision. The article describes a study in which subjects were asked to make a number of decisions and each subject was given the option to decide immediately or deliberate while performing an unrelated task. The researchers found that subjects who answered immediately made the best decisions and that “the longer our participants thought about their answers, the more likely they were to include irrelevant information at the expense of relevant information.” The article concludes that “conscious deliberation, however long and careful, can be a surprisingly crude and ineffective tool.” a) Is this study observational or experimental?

This study was an experimental study. The study was divided in two big groups, the ones deciding immediately and the others deciding while performing an unrelated task where the researchers compared the results from the two groups.

b) Can you think of a confounding factor here?
I consider the age variable plays an important role in the study, depending of age the response to different situations might vary. Other big confounding factor might be monetary, people with a job tent to make different decisions that jobless people.

c) If you could re-design this study, how would you do it?
To avoid confounding factors, I would have divided the group by age, gender and income per year, however I understand some university experiments do not count with the budget or the population to get more accurate results.

Chapter 2.

33. The file stockprices.xls (an excerpt in in table 2.12) contains the daily closing prices for 100 different stocks over a thirty-day period. Which stock showed the most price variability? Which stock had the highest average price?

Table 2.12. An excerpt from the file stockprices.xls
3/2/07| 299.65| 81.65| 287.28| 278.08|
3/1/07| 302.56| 81.02| 291.05| 278.96|
2/28/07| 300.13| 81.82| 288.47| 281.84|
2/27/07| 302.52| 82.44| 281.69| 281.26|
2/26/07| 303.94| 83.96| 283.18| 282.77|
2/23/07| 303.78| 85.68| 288.52| 283.37|
2/22/07| 304.62| 86.34| 292.59| 284.41|
2/21/07| 301.08| 85.06| 293.19| 284|
2/20/07| 299.1| 85.3| 294.68| 283.14|
2/16/07| 308.05| 83.11| 301.33| 284.8|

The SOM stock price shows the highest price variability with a standard deviation of 16.047. The BTX stock at $309.7 average stock price has the highest average stock price of all stocks

35. The file ordersizes.xls (an excerpt is in Table 2.14) contains...
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