Statistics Paper

Mini-Project 1 will involve taking a random sample (in the true sense of the word) from a well-defined population and measuring a categorical variable. Before you collect the data, you should make a conjecture as to the value of the population proportion.

(e.g., more than 60% of Cal Poly students own a cell phone, more than 1/3 of TV commercials during the NBA playoffs last longer than 30 seconds, less than 75% of San Luis drivers come to a complete stop at intersections next to campus, a majority of college students can distinguish between the taste of Coke and Pepsi, more than half of a random sample of products are more expensive at Scolari’s than at Lucky’s). 

The sample size should be at least 30 and the population should be at least 20 times the size of your sample. The type of study can be an experiment, an observational study, or a survey. The key requirement will be that you randomly select the observational units from the larger population. (Note: the sample does not have to consist of humans. You should be very careful in how you define your population.) You are free to choose your own topic(s). The topic may be related to your major or another topic of interest. Make sure you choose a topic so that it is straightforward to gather the data or you have access to data from another class or professor. You may work with one other person or complete by yourself.

The Study:  You are free to choose your own topic. You should think of two groups that you can compare with one categorical variable through an experiment or an observational study.  Make sure you choose a topic for which it is feasible to gather the data in a relative short period of time. The question may be related to your major or some other topic of interest. For example, you could observe men and women on campus to determine whether they are left or right handed, or you could randomly assign people to take a survey with two different wordings and see if they respond differently depending on how the question is asked. Your study must obtain at least 10 observational/experimental units in each explanatory variable group.

Final Report:  Due April 10th. This should be a typed report, written collaboratively by all team members. Your report should be written as to other student researchers. Make sure it includes at least:

I. Introduction – Why did you choose this topic? What did you expect to find? Have similar studies been done elsewhere? Why should the reader be interested in your results and continue reading? What are your plans and goals?

II.  Summary of Data Collection Methods – How did you collect the data? What were the experimental/observational units? What groups did you compare, how did you find them/form them? Was this a prospective or retrospective study? Observational or Experiment?  What was your response variable? How were these variables measured? What additional “controls” did you exert on the study? (E.g., did you only observe people writing or did you take any behavior such as throwing a football as indication of handedness?) Any “operational definitions”? (E.g., did you pre-test any of the questions on a test group to see if the wording was clear?) Did you have any problems with non-response or other unexpected results? Did anything go wrong during the course of the study? (Note: You can never give me too much detail in this section!) In particular, there should be enough information that someone else could replicate your study on their own based only on your description (and hopefully improve upon it based on your suggestions below).

III.  Analysis of Results – Include appropriate numerical and graphical summaries of your data. Write several paragraphs explaining what you found in these data. Your typed explanation of your statistics project will have the following criteria: Table of values, this should include the mean and standard deviation of each column, completed scatterplot/graphs with title and axis labels, typed up explanation of the meaning standard deviation, explanation of your line of best fit (explain what the slope and y-intercept represent), and what the correlation coefficient reveals about your data, line of best fit and R^2 displayed. Include the p-value and a careful interpretation of what this p-value tells you. Is the difference between the groups statistically significant? What conclusions can you draw? Be sure to refer back to the type of study conducted in explaining the scope of your conclusions. Address both the question of causation and the question of whether you believe your findings generalize to a larger population. (Note: All computer output should be included in the body of the report. Make sure all figures and graphs are clearly labeled.)

IV. Conclusion – Summarize the results of your study. What did you learn? Did the data behave as you expected?  Critique the methods used to collect the data. Is there anything you would do differently next time? How might this affect the conclusions of the study? What similar questions might someone chose to investigate in the future to build on your results?

Previous Project Ideas:

Compare people arriving to a location with elevators and stairs to see if one gender uses either mode of transportation more often.

Survey men and women to see if one gender tends to bicycle to campus more often

Do freshmen call their parents more often than upper classmen?

Are people more likely to agree if you randomly decide to ask them “Are you happy with your roommate” or to disagree if you ask them “Are you unhappy with your roommate?”

Are people more likely to support the war in Iraq if you phrase the question differently?

Are freshmen more likely to think they will change their major at UGA than transfer students?

Does listening to classical music while studying a group of words improve whether subjects can pass a threshold level of recall?

Do self-identified chocolate lovers prefer the taste of Ghiradelli chocolate to Nestle’s?

Are people more likely to loan you money for a phone call depending on how you are dressed?

Are women more likely to respond if you sneeze near them?

Does class time have any effect on caffeine consumption and in what form do students get their caffeine, soda or coffee?

Tell people they are tasting two different types of muffins and see if they are more likely to predict the second taste of the same muffin.

Are people using their cell phone less likely to come to a complete stop at a four way intersection?