Math 112 project

1. Math 112 project Actualize our understanding of the big ideas we’ve learned about Statistics

2. Big Ideas • Ask the right question • Organize, summarize data • Look for patterns in the data • Interpret data, draw inferences

3. Ask the right question Type of study : observational or experimental • Observational studies : you can use surveys • Most students will readily fill out a short survey • Surveymonkey.com is an option • Experiments : these can be fun! • Taste tests: e.g. Can students distinguish expensive bottled water from less expensive water or tap water? • Identifying subtle (or abstruse) shades of color: are male and female students equally adept?

4. Ask the right question (cont) • Identify the variable(s) • If interested in association between categorical variables, look at Section 3.1 (we skipped it). • For a categorical variable, perhaps a Pareto chart is appropriate • Identify the population • Identify the sample (as representative as possible) • Getting a simple random sample is difficult • Doesn’t mean you should settle for asking your friends or people on your hall in the dorm.

5. Ask the right question (cont) • Identify the sample (continued) • Set up outside a place where you will likely see a cross section of your population. • See if you can get at least 30 to complete your survey. The simpler the survey, the more success you are likely to have getting meaningful answers • Can you phrase the question(s) using some form of what we have studied? This will allow to use your new knowledge and skills. Plenty of time later for more complicated questions.

6. Organize, summarize data • Get the data - surveys • Questionnaire : n = at least 30 • Ask only the questions needed (2 or 3 questions raise the likelihood of getting students to carefully complete the survey). If you won’t use the data, don’t ask for it! • If the person answering the survey must answer a certain way before the survey is useful(e.g. # of drinks per week > 0), be careful : what if most people put 0? You must get many more survey responses to get an effective survey size of 30.

7. Organize, summarize data (cont) • Surveys (continued) • Test your survey. Have a few of your classmates take the survey, and get their comments. May save you a lot of grief. • If a convenience sample, make it as random as possible (don’t just ask your friends – set up outside the mess hall, perhaps, or some location where you expect a reasonable representation of your population of interest)

8. Organize, summarize data (cont) • Internet: be careful about documentation (see project assignment – use MLA format) • Summarize with numerical summaries, box plots, or other techniques we discussed • Include data in an appendix of your report

9. Look for patterns in the data • How are the data distributed? (mound shaped, skewed, symmetric – what is the shape of the distribution?) • Analyze the data based on assumptions that can be made from the distribution

10. Interpret data, draw conclusions • Correlation • If you are reporting correlation, there is a simple test for whether correlation is significant – (TI 83: Stat->Test->LinRegTTest. Same as test for a non-zero slope for linear regression). • Don’t forget: Correlation does not imply causation. Some topics suggested that you had forgotten this. • Linear regression • Confidence interval (proportion, mean) • Significance tests