Summary: For those who may not have email, or have a problem retrieving it, this page contains all the emails that were sent to the whole class. If you’re not on the mailing list and want to be, please add your address to IQ Web.
Contents:
Greetings, statistics buffs!
It’s time to start planning for the ESP lab and the Field Project. The ESP Lab counts about an eighth of your grade and is due Tuesday after next; the Field Project counts about a quarter of your grade (plus a significant block of possible extra credit) and is due the last Tuesday before the exam. Please look for them both under Assignments on the class Web page.
Each one has a detailed grading rubric. I urge you to use that as a checklist to make sure that you get the best possible grade.
I don’t read draft writeups, but I’ll be happy to answer particular questions in person or by email. Remember that the Baker Center is also there to help you. (Using standard English is part of the grade for both assignments. You may want to work with a writing tutor.)
Suggestion: do the data collection for the ESP Lab this weekend, and the data analysis next week. That leaves you next weekend to review your work and catch any errors or omissions.
A word about the Project Plan:
In the past, several students in each class ended up picking a project that didn’t meet the criteria for inferential statistics. To prevent this kind of disaster, you will negotiate a Field Project Plan (also under Assignments) with me before you start collecting data for your Field Project. The due date is Dec 2, but experience shows that most students need to revise their plans a couple of times before they are ready, so the time to start thinking about your project is now.
You know now what a hypothesis test is. By the end of the course we’ll be doing hypothesis tests with binomial, categorical, and numeric data for one or two populations, so you’ll probably have no difficulty coming up with an idea for a project that interests you.
Suggestion: Email me a one-sentence project idea as soon as you can, and before you go to the trouble of writing up a Field Project Plan. Then have your plan written no later than Nov 25, to allow time for the revisions that will probably be needed. You can email me your plan for discussion in email or hand it to me on a Tuesday, but email will be faster.
Caution: Getting your Field Project Plan approved by the end of class on Dec 2 is part of your Field Project grade, and only if you have a plan approved by that date will you be able to present your Field Project to the class for extra credit the following week. Do not put the Field Project Plan off to the last minute.
These have been posted to IQ Web and you may pick them up there. I will have printed grade computations for you next Tuesday.
The grades are S (Satisfactory, C or better), S− (less than satisfactory, D− to C−, 60–72), and U (unsatisfactory, below 60%).
These grades are not sent outside the College, but are for your use in assessing your progress. Please feel free to ask me any questions in person or in email, though I can’t answer email questions about your grades if I don’t have a signed Email Waiver from you.
Please note: I may not have email access from today through Monday, but if you send me email and don’t have a response by Monday 8 PM please send it again.
Questions 2 and 4 were troublesome for many of you. Please review carefully the solutions on the Web page and make sure you understand where you went wrong. (I have just revised both of them.)
There were a couple of misunderstandings I wanted to address.
Several of you interchanged the x and y axes in your scatter plot. While this doesn’t affect the correlation coefficient, it does affect the regression equation. x and y were specified in the data collection table.
Also, a few of you mixed men and women in your sample, but the directions specifically said to take a sample of the same gender as yourself. There’s no reason to think that men and women would follow the same distribution, though it could be interesting to test this. But without some proof up front, you can’t use a mixed sample to predict anything about a man’s or woman’s shoe size.
Greetings, statistics buffs!
As you may know, the College is changing its email server and software over the weekend. While the IT folks don’t anticipate any problems, there might be a delay in my receiving your emails or in my responding to you.
If you send me mail over the weekend and don’t have a reply by Monday afternoon, please send it again. Thanks!
Greetings, statistics buffs!
There are quite a few formulas in Chapter 5. While they have their uses, there’s no substitute for common sense. When you read a problem, make sure you know clearly what the given conditions are and what you’re supposed to find. Don’t just grab a formula and apply it, hoping it will fit.
In the past, most classes have had a lot of trouble with the quiz on Chapter 5. You can buck this trend by being thoroughly prepared. Make sure you do all the homework, plus extra problems on any concepts you’re having trouble with. And make sure you work the timed practice quiz and check your answers; again, get help for anything you don’t understand.
See you tomorrow night!
P.S. Remember that the Shoe-Size lab is due promptly at 6:30 tomorrow, and remember to staple it before you come to class.
Greetings, statistics buffs! As promised, I queried the textbook author about the table on page 242, and here is his answer:
Thanks for contacting me. I am not sure that I have a satisfactory explanation to your inquiry. However, the Census Bureau has the following footnote for married individuals: Includes people who are married with spouse present, married with spouse absent, or separated. Perhaps some folks who are “married with spouse absent” or “separated” actually indicated that they were divorced. In addition, this data ... excludes members of the Armed Forces living on a base. Finally, the data is based on the Current Population Survey, which is a survey of about 60,000 households that extrapolates to the general population and most certainly has some sampling error. In fact, this survey also has non-sampling error resulting from an 8% non-response rate.
I hope you and your class find these explanations satisfactory. Also, the data is from the statistical abstract. The most recent data is for 2006 (from the 2008 Abstract), and is Table 56 under population.
Greetings, statistics buffs!
If you have a modern browser or IE7, you’ll probably notice narrower lines on the Web pages, to make for easier reading on line. (IE6 users won’t see any change.)
If you print anything, it will still use the full width so as not to waste extra paper.
Greetings, statistics buffs!
Make sure you’re getting the most out of your study time. You’ll find some tips in How to Study Math, under Handouts | General Math on the Web page.
If you find yourself struggling with the homework, get some help in the Baker Center and work extra problems on the concepts that are bothering you. The assigned homework problems are a minimum, not a maximum.
Also, I strongly recommend working the practice quiz each week, giving yourself the indicated amount of time. That can point out areas that you need to give some extra work to.
It should go without saying that you show up on time and stay for the whole class. I know it can be tempting to duck out at the break, but ask yourself whether that’s really a good idea in terms of learning the material for the next quiz.
Greetings, statistics buffs!
The health center tells me that there are a couple of infections running through the College. Please, if you’re ill, consider your own health and your classmates’ health and stay home.
If you’re not well enough to stay for the whole class, you’re probably not well enough to be in class in the first place, and you’d be better off home in bed.
Your grade won’t suffer — the quiz will just be one of your two freebies.
Greetings, statistics buffs!
Just a reminder: the shoe-size lab is due in thirteen days. Please get it from the Assignments menu in the Web site.
Greetings, statistics buffs!
In preparation for next week, remember to skim-read Chapter 4. Your red schedule sheet tells you to replace objective 4 of section 4.1 with the handout Decision Points for Correlation Coefficient, which you’ll find on the Web under Chapter 4. I have the two calculator procedures printed and will hand them out in class, but please practice the first one on your own before class to make sure you can find all the keys and menus.
I’d like to suggest you take a look at two short handouts under General Math, How to Take a Math Test and How to Work a Math Problem. They can help you get the best results for your time on quizzes and homework.
Greetings, statistics buffs!
As you know, descriptive statistics is about presenting center, spread, shape, and outliers. Last night we had numeric measures of center and spread, and even a numeric measure of whether a data point is an outlier (though it’s easier just to look at the modified boxplot). But what about shape? Are there any numeric measures?
Yes, there are: skewness and kurtosis. I believe you all have the program SKURT that computes them — if you don’t have it and would like it, just ask.
Skewness goes beyond a simple “skewed left” or “skewed right” to numeric measures of the amount of negative or positive skewness. Kurtosis is a little harder to grasp, but it measures how “peaky” a distribution is relative to a bell curve.
Naturally there’s a Web page. If you’re interested, check out Skewness and Kurtosis on the TI-83/84 under the Chapter 3 handouts.
Greetings, statistics buffs!
I meant to talk about the names of shapes of distributions, page 80 in your textbook. These are the four most common types, though there are others. Two notes:
Remember that height = frequency or relative frequency, so in a distribution that is skewed right, most of the population has low scores but a few individuals have high scores. The classic example is salaries at a corporation: most people’s pay is on the low end, but you have managers making more, some upper managers making more still, and a few executives making top dollar. Another example is ages in a developing country: the bulk of the population is young, with fewer middle-aged and only a few very old. In developed countries, the distribution of ages is still skewed but to a much lesser degree.
As mentioned in class, solutions to both quizzes are available on the Web page. From now on, they’ll be on line by the end of class unless I announce otherwise.
If you haven’t yet, take a look at the main page of How to Succeed in Math, under Handouts | General Math. There are a few short tips there to help you do well. The Baker Center can help you with your study techniques as well as specific statistics issues.
Greetings, statistics buffs! The first chapter of the book is a little dry, but it’s the foundation for everything else we do. You should especially be concerned with data types and with the differences between good and bad types of samples.
As I mentioned in class, my lecture notes are among the handouts for each chapter.
In the same section, you’ll also find a practice quiz. While the homework problems are important, many students also like to take the practice quizzes because I wrote them, so you get an idea of how I phrase things on the real quiz. Also the practice quizzes have suggested times, which you should take seriously. If the suggested time seems too short, you want to get more familiar with the material.
In the Handouts menu under General Math, you’ll find a series of short pages called How to Succeed in Math. Math isn’t harder than other subjects, but you have to approach it differently, and you might like to know how to get the most benefit from your efforts. I know you already have a lot of reading for this week, so I suggest How to Read a Math Book to help you make the best use of your reading time. Over the next few weeks, I’ll remind you about the other papers.
As always, I’m happy to answer questions in email.
Greetings, statistics buffs! This mail has two purposes: first to make sure your email is working, and second to remind you of what you’ll need for statistics class.
It will be helpful but not essential to have both these items before class this evening.
One item is a TI-83 or TI-84 calculator. Please see the class Web site at http://www.tc3.edu/instruct/sbrown/stat5008c/ for details. This is a good time to buy, as most of the “big box” retailers are running specials. You’ll absolutely need this by next Tuesday.
The other item is either the textbook or the online access pack, not both. Please see the same Web page. You’ll need this pretty soon because there’s a substantial amount you have to study for next Tuesday.
Questions? Please feel free to ask! (Note: I try always to respond to emails within 12 hours, and usually much sooner.)
Greetings, statistics buffs! For some of you this is new, for others a reminder. Here is advance notice of what you’ll need for class.
One item is a TI-83 or TI-84 calculator. Please see the class Web site at http://www.tc3.edu/instruct/sbrown/stat5008c/ for details. This is a good time to buy, as most of the “big box” retailers are running specials.
The other item is either the textbook or the online access pack, not both. Please see the same Web page.
Questions? Please feel free to email me!
Greetings, early birds! I thought you might appreciate advanced notice of what you’ll need for class.
One item is a TI-83 or TI-84 calculator. Please see the class Web site at http://www.tc3.edu/instruct/sbrown/stat5008c/ for details. This is a good time to buy, as most of the “big box” retailers are running specials.
The other item is either the textbook or the online access pack, not both. Please see the same Web page.
Questions? Please feel free to email me!
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For updates and new info, go to http://www.tc3.edu/instruct/sbrown/stat5008c/