Saturday, September 3, 2011

BUS504: Modules 1-5; RES600: Modules 1-3

I am actually surprised that people have been reading my blog... I have not updated it in a while but I will do my best to allow others to see what I have written so far.

For my BUS504 course, here are my essays:

Module 1:
Case
SLP

Module 2:
Case
SLP

Module 3:
Case
SLP

Module 4:
Case
SLP

Module 5:
Case
SLP

Unfortunately I do not recall what grade I received for each assignment, however, the overall grade for the BUS504 course was a B+.

I am currently taking RES600 - Introductory Data Analysis.  This will be my last course at TUIU as I am transferring back over to University of Phoenix.


Module 1:
Grade A: Case
Professor comments:
Alexandria,

In this assignment you were asked to identify the key research question in the study presented, distinguish between types of variables, and provide relevant descriptive statistics to include frequency tables, box plots and other relevant statistics.  You were also directed to give a go at using the cross tabs function.  You were also asked to comment on these various findings in relation to the variables considered most and least important to kids in relation to defining popularity …and you were asked to provide some other observations. 

Overall I like what you did.  I did not see where you clearly and specifically pointed out the key research question, though you did allude to it.  Also, you might want to spend some time pondering if Grade might be better construed as Interval data.  From the start of one grade to the start of another is one year.  Thus, there is a constant distinction or interval between grades.  At the same time, there is no zero value in K-12. 

Still, you seem to understand the fundamental concepts presented in the assignment and I appreciate your hard work.

Dr. C


Grade B+: SLP
Professor comments:
In this assignment you were asked to identify the data type for a series of variables.  You were then presented with a coding scheme for categorizing income data and asked to comment on it.  Finally, you were asked to provide a frequency table and calculate the mean, median and mode for speed limits in various countries. 

Overall you did a good job with this assignment.  I think, however, that for the nominal data categories such as marital status and whether a person has been unemployed, the mean has very little meaning.  Here it seems that frequencies, proportions and the mode would be the appropriate descriptive statistic.  Also, I was hoping for a bit more comment on question 2.  At the doctoral level your response to any given question should be quite in-depth. 

Keep up the good work!!

Dr. C



Discussion forum: Grade A
Academic/Scientific research What is Academic/Scientific research? Bring your multidisciplinary viewpoints to support your arguments.
Academic/Scientific research consists of data analysis and formulas. This data analysis looks to prove or disprove hypotheses. The main objective is to learn, discover, and investigate the integrity of the data. What academic/scientific research can bring to society, science, individuals, etc. is proven information that people can learn from or expand upon.
  
Module 2:
Grade B+: Case
Professor comments:
Alexandria,

In this assignment you were asked to put together a simulation mimicking 500 series to determine using a simulation experiment what the likelihood is of World Series sweeps.  You were asked to discuss this in terms of probability and statistics and to provide your result and some basic graphical analysis. 

There were two ways to do this with SPSS.  One involved the use of a syntax editor and the second way to handle this was provided in a wave file tutorial. 

You used an Excel statistical product, which is fine. 

Overall you appear to have done what you were asked to do except I did not see the pie chart of your outcome, and I think it would have been good to provide some explanation regarding the differences in calculated probabilities and actual series outcomes.  For instance, clearly teams are not always evenly matched.  There are also other potentially spurious variables such as home team advantage among others.  Also, I did not see where you extrapolated to additional series outcomes such as a series going 5, 6 or 7 games.  Regardless, you did demonstrate some critical thinking and a grasp of the fundamental concepts presented in this module.   

Dr. C


Grade A-: SLP
Professor comments:
Alexandria,

In this assignment you were asked to identify the appropriate distributions for various data types, distinguish between a few terms related to sampling, and to show how to calculate World Series probabilities for winning games 5, 6 and 7. 

In short, the information provided for assigning distributions was a bit vague in most accounts and required a little ‘qualifying’ of the information to be able to intelligently argue for one type of distribution or another.  I think it would have been good for you to describe why you thought the distributions you selected would fit the data set described.  Also, a number of students selected to use an abbreviation for a binomial expression in their probability calculations.  I don’t really have a problem using this approach and I noted you used this approach as well.  You did a good job with this part of the assignment. 

Dr. C



Discussion forum: Grade B+
Interesting Probability Question Let us look at a very interesting probability question here: In a certain televising game show, a valuable prize is hidden behind one of three doors. You, the contestant, pick one of the three doors. Before opening it, the announcer opens one of the other two doors and you see that the prize isn't behind that door. The announcer offers you the chance to switch to the remaining door. Should you switch, or does it really matter? (Hint: you may use conditional probability)

You are welcome to share your thoughts and clues here and it can be a collaborate effort. The final answer may not matter as long as you show your logic reasoning here.

The initial probability of opening the correct door is 1/3 or 33%, since there are 3 doors and you can only finalize one.

"...the announcer opens one of the other two doors and you see that the prize isn't behind that door..."

It doesn't really matter if the contestant switches or not because the odds of winning will always be slim.

If the contestant picks correctly (door 1), and door 2 or 3 is randomly opened and reveals that there is no prize, then there is a 1/2 chance between the contestant's choice and the announcer's choice and cannot open door 1 to open.
door 1 probability=0
door 2 probability=1/2
door 3 probability=1/2

If the contestant picks door 1 but door 2 has the prize, the announcer will pick door 3.
door 1=0
door 2=0
door 3=1

If the contestant picks door 1 but door 3 has the prize, the announcer will pick door 2 to open.
door 1=0
door 2=1
door 3=0

This is only if the announcer does not reveal the door with the prize.

There is a second set of probabilities if the announcer does show the prize if the contestant picks door 1.

door 1=0
door 2=1/2
door 3=1/2

Module 3:
Grade A: Case
Professor comments:
Alexandria,

You did a good job with this assignment.  Your reasoning was easy to follow and you did a good job of following directions.  I think the key point of this assignment is to give students some 'hands on' experience with sampling distributions.  I like that your 'experiment' tended to demonstrate the Central Limit Theorem as well.  Both concepta are important fundamentals of statistics. 

You seem to have done everything that was required of you.  Good work!

Dr. C


Grade B+: SLP
Bonus: SLP with comments from professor
Professor comments:
Alex,

Please see the attached feedback file... 

Dr. C



Discussion forum: Grade N/A
Understanding Polls -- Confidence Interval Many newspapers, when reporting results of political polls, say that “with 95% confidence, the results are in error by no more than +/- 3 percentage points.” The typical sample size is about 1500. This allowance for error is intended to cover both sampling variability and the effect of small biases.

a) Assume that the poll (sample) indicates that just about 50% of likely voters favor a particular candidate. How large a +/- term is required for a 95% confidence interval for the population proportion.

b) Would the +/- term be much different if 40% of likely voters in the sample favored the candidate.

c) Why is the quoted +/- 0.03 larger than the +/- term you calculated in question a)?

Many newspapers, when reporting results of political polls, say that “with 95% confidence, the results are in error by no more than +/- 3 percentage points.” The typical sample size is about 1500. This allowance for error is intended to cover both sampling variability and the effect of small biases.

a) Assume that the poll (sample) indicates that just about 50% of likely voters favor a particular candidate.

P = 50% (or .5) of voters that favor the candidate
n = 1500 is the sample size
standard deviation sample proportion (p) = sqrt[P(1 – P) / n] (Stattrek.com, 2011)

p = sqrt[.5(1 - .5) / 1500] = sqrt[.25 / 1500] = sqrt.0001666 = 0.0129

Confidence Interval (z) = 1.96 (Bioconsulting.com, n.d.)
Confidence (C) = 95%
Confidence interval with level C (N) = (1-C)/2

N = (1-.95)/2 = .05/2 = .025

Margin of error (m) = z * p / sqrt N (Mackowaik, et al, 1992)

m = (1.96 * 0.0129 / .025)² = (.025284/.025)² = 1.01132² = 1.0228

b) Would the +/- term be much different if 40% of likely voters in the sample favored the candidate.

P = 40% (or .4) of voters that favor the candidate

p = sqrt [.4(1 - .4) / 1500] = sqrt [.24 / 1500] = sqrt.00016 = 0.0126
m = (1.96 * 0.0126 / .025)² = (.024696/.025)² = .98784² = .97582

c) Why is the quoted +/- 0.03 larger than the +/- term you calculated in question a)?

The quoted +/- 0.03 might have been larger than the +/- term I calculated because the quote may have come from different standard deviation calculations and may need more information, such as other samples to calculate the question more appropriately.

Stattrek.com (2011)
http://stattrek.com/ap-statistics-4/standard-error.aspx
Mackowiak, et al (1992)
http://www.stat.yale.edu/Courses/1997-98/101/confint.htm
Bioconsulting.com (n.d.)
http://www.bioconsulting.com/calculation_of_the_confidence_interval.htm


Module 4:  in progress


I honestly felt that this was the hardest course I have had to take in a long time.  I am really dreading taking any more statistical courses.  I thank my professor for being very generous with his grading methods as I am very new to this type of course and mostly tech savvy.