Statistics 309H

FAQ: Homework & Exams

The textbook pages in the reading packet do it differently from the way you did it in class. Can I solve the homework and exam questions using the procedures in the reading packet or do I have to do it your way?

It's true that I will sometimes use procedures that are slightly different from those in the textbook. For example, sometimes the book will offer a simple formula or an analysis using tables whereas the approach I use in class may take longer.

Unless a particular approach is explicitly asked for, you can solve problems using any method you choose. However, I note that the reason I sometimes stray from the textbook is that I believe that my approach has additional conceptual value. And sometimes I will ask questions that test that conceptual understanding. My advice, then, is that if you plan to use formulaic shortcuts you should be sure to understand the approaches that I use in class as well.

What do we need to know about the articles in the packet for the exams?

All of the articles include points that are relevant for the weekly statistics topic. For example, the appendix by Kolata (1990) on coincidence is relevant to week 1 because it discusses the idea that any particular coincidence may seem unlikely yet the chance are that some such coincidence is likely. Notice how the article discusses aspects of what we identified in class as 'The selection fallacy' without naming it. Similarly, the 2001 article by Paulos ("In tragedy, the nonsense of numbers") makes points that are relevant for our discussion about how people search for and find patterns in numbers when they are overwhelmed by fear or grief.

In short, you are expected to understand the central principles of the articles and to be able to relate them to the lectures and textbook material. You will not need to know minutia or even the author's name. However, you will need to know what a question is referring to if it asks about, say, "the Gould article on his life-threatening disease."

If the textbook portions of the reading packet cover things that aren't discussed in class and that aren't relevant for the practice problems or homework, must we know these things for the exams?

No. 

I've finished the practice problems and homework assignment -- will you supply additional problems for me?

No, but you can find additional problems (with answers) in almost any standard statistics textbook.  The library is loaded with such books.  Also, check out the many statistics links on our class website.

What else can I do to study for the exams?

As you know (or will soon find out), I provide you with a lot of material in this class.  You have class notes, textbook chapters and other articles in your reading packet, occasional handouts, website links, practice problem sets, etc.  These are the materials that you should focus on.  There is no magic bullet, and there are no additional problems that I have held back from you.  The things you have are the things you should study.

The hardest parts of this class are the conceptual parts rather than the mechanical parts.  One of the best things you can do to teach yourself the material is to generate a variety of problems on your own that are similar to those that have been assigned.  Sometimes you'll get stuck. When you do, you might want to ask your classmates, the TAs, or me about it. Feel free to use e-mail when communicating with us about this.  Also, you should rewrite and organize your class notes.  Doing so may make you aware of gaps in your knowledge that you can look up in the textbook or online. 

If you prefer to meet with a TA or me in person, be sure to send us the problems that you've generated BEFORE the meeting, along with your solution, or partially worked solution. This gives us a chance to think about it, work it out, and identify a good way to explain the problem before talking to you about it.

Why didn't I do well on the exams?

• I blanked out
• I needed more time
• I knew everything except the things that were worth the most points on the exam
• I do well on the problems, but not so well on the true/false and multiple choice
• I studied really hard, but my performance doesn't reflect that effort
• I worked all practice problems, got every homework problem right, and I still didn't do well on the exam

These are the most common things students say to me after they did not do as well as they hoped and expected on a statistics test. Statistics is a subject that often requires a lot of study on a regular basis rather than a lot of cramming one or two nights before an exam.  Even successful completion of homework assignments doesn't come close to guaranteeing good performance on an exam.  Why?  Because good performance in statistics requires a level of conceptual understanding that goes beyond the ability to apply a formula or technique.  You know that you understand the topic well when you can read a problem, take some notes from it, and decide for yourself which of many principles and techniques are relevant for solving it.  Understanding the techniques is not synonymous with understanding which techniques apply in which situations. The latter takes a lot of time and practice.

Once again (see above), a good way to increase your understanding of the material before the next exam is to try generating your own problems and working out the solutions. Alternatively, try altering the homework and practice problems slightly to produce a different problem. If you get stuck, see me or the TA.

All of this should be done weeks before the exams. You are taking a big chance when you choose to do these sorts of things two days before an exam. Sometimes you will get lucky and your last minute efforts will lead to a good grade. But sometimes it will not. If you live dangerously in this class (i.e., if you don't keep up with the principles as we cover them in class or fail to follow the recommendations above) you must be prepared to suffer the consequences in your grade.

To those of you who do prepare well in advance and still struggle, make an appointment with me. Prepare a list of specific questions and problems for our discussion.  I'll do my best to help you and to make recommendations.  I can't help very much if you come by for the first time a few days before an exam. And there is nothing that I can do for you after you have received a lower grade than you expected or wanted.

I interpreted the question on the exam differently from what you wanted.  Based on my interpretation, isn't my answer right?

On some exam questions, it may be possible to apply an interpretation that is different from the one that a careful reader of the question would apply.  This is not a sufficient basis on which to argue that the question is ambiguous.  If the interpretation is widespread, then you have a better case for ambiguity.   

Sometimes students will say, “I just assumed X, and answered the question with this in mind.”  However, you are not justified in assuming anything unless question specifies it.  For example, some people will say “I just assumed that the events were independent, and did the calculation for independent events.”  In this case, if the problem does not specify independence, an answer that assumes it is likely to be wrong. 

Whenever you have a question about a question, you must ask.  You are not entitled to make your own assumptions and then receive credit for solutions that are unique to your interpretations.

Will there be SPSS computer material on the exams?

Yes. You will be expected to be able to interpret SPSS output of the sort that we covered in class.

Will the Final Exam be comprehensive?

Yes, the Final Exam is cumulative (i.e., includes all material from the course).  About 40% of the Final Exam will be based on material covered after Midterm Exam #2.

What do we need to know from the reading packet for the Final Exam?

All of the material in the reading packet is relevant for the Final Exam.  However, I will not ask questions about specific articles that you read in preparation for Midterm 1 and Midterm 2.

If my grades improve (or decline) throughout the semester, will you take this into account when determining my final grade?

The only fair way to grade is to tell you how much everything is worth up front and then to stick with those percentages.  Of course, if your performance improves that will be great news for you because the Final Exam receives the most weight.

Will you return the homework assignments so that we can study from them?

I will return the homework assignments but, because they are due right before the exams, you will not get them back before the exam.  However, I will post the answers to the homework assignments right after you turn then in so that you can have this information when you study.  Therefore, you should keep a copy of your homework.

Will you return the exams so that we can study from them?

I will not return the Midterm Exams. However, you may look at them during a TA help session. Send me an e-mail if you want to see your exam so that I can make sure that one of the TAs has it. You may not take the exams away or copy questions and answers.

Can I make up a homework assignment if I miss the deadline?

No. The homework deadlines will not be extended.  (As noted above, I will post answers to the homework assignments immediately after the due date.)  Please plan accordingly.  If you fail to turn in an assignment (or turn it in late), you will be assigned a score of 50%.

Can I make up an exam if I miss it?

As noted in the course details, there are no make up exams during the semester.  By this I mean there are no circumstances when you will be permitted to take an exam during the semester after the scheduled exam date. 

However, if you know or strongly suspect that you are going to be absent on an exam date for good cause (e.g., religious holiday), you must contact me in writing at least two weeks before the scheduled exam date to request an early exam.  Be sure to include a full explanation for your planned absence, including supporting written documentation.  If approved, you will take the exam 1-2 days before the scheduled exam. 

If you miss a midterm exam for more sudden reasons (e.g., illness, injury, urgent family matters, etc.) -- and you provide me with some documentation where appropriate (e.g., letter from your physician) -- I will weight your final exam 50% of your grade (rather than 35%).  If you miss a midterm exam and don't present an acceptable excuse, you will be assigned a score of 50%.

If you miss the final exam and have an acceptable excuse, you will receive an incomplete for the class. You will resolve the incomplete by taking the final exam at the beginning of the summer session.  If you miss the final exam and don't present an acceptable excuse, you will be assigned a score of 50%.