Hi everyone,

A few people were having trouble with problem #1 — webwork was not accepting the test statistic, even though their calculations were correct.  I have updated the problem to give a more accurate xbar (that is, it now shows 3 decimals instead of 2), and if you use this to calculate the test statistic it should solve the problem.  If it doesn’t, please let me know.  Apologies for the inconvenience.


Mr. Reitz

WeBWorK #11

Hi everyone,

WeBWorK assignment #11, which is based on the material covered in class today (“sample means”), is now available.  It will be due next Tuesday evening, 4/30/13.  Please do not work on it until after the exam on Thursday.  Indeed, it would be best if you did not even read this message until after the exam.  Best of luck with your studying.

– Mr. Reitz

Update on WeBWorK #10

I have rewritten the WeBWorK #10 assignment – the problems are based on section 5.5 (which we studied on Thursday), and are much more similar to what will be on the exam next week.  The assignment is now available, and is due on Tuesday night at midnight.  Don’t hesitate to write if you have questions.

Take care,
Mr. Reitz

Class Updates: WeBWorK, Exam #3, my black eye

A few important items:

  1. Yes, I was indeed in a bike accident today.  I was lucky and walked away with a few scrapes, 3 stitches and a black eye.  You can check out the damage on Thursday.  Here is card that my almost-4-year-old daughter made for me – she says it is a picture of “funny smiling people, to make you laugh,” but I swear the one on the right looks just like me sailing through the air over my bicycle.
  2. The deadline for WeBWorK #9 has been extended to this Thursday, April 18th, at midnight.
  3. WeBWorK #10 is ON HOLD for now — the deadline and problems may be changed.  Don’t work on it for now.  I’ll give you an update on Thursday.
  4. The third exam, scheduled to take place next Tuesday, is postponed by one class day.  The new date for the third exam is next Thursday, April 25.  A review sheet is available on the Handouts page, and will be distributed in class this Thursday.

Take care, and be safe,
– Mr. Reitz


UPDATE MONDAY 4/15/13:  I found that for some (but not all) students, problem #8 was also having similar trouble.  It is fixed, as of 8:23pm.

Hi everyone,

It was pointed out in class today that some of the problems in WeBWorK #9 were being marked incorrect, even if you follow exactly the steps described in class.  I have tracked down the source of the error, and updated a number of problems in the assignment — they should all be working properly now.

Unless further problems are discovered, the due date for WeBWorK #9 will remain next Tuesday, April 16, at midnight.

If you believe that a problem is still not working correctly (that is, you think your answer is right but WeBWorK is not accepting it) please send me an email and let me know.

– Mr. Reitz

ps.  If you’re interested (GEEK ALERT), the errors arose because we use a table to find z / probability, and the table is limited in the number of decimals it will provide.  Solving these problems on a calculator gives more decimals of accuracy (but requires a more specialized calculator, such as a graphing calculator)

WeBWork #1: UPDATE

This is just a quick update regarding problem #8, since it includes something you have not yet seen:

When a stem-and-leaf diagram contains TWO ROWS for each stem (for example, “18” appears at the start of the first and also the second row), the convention is to split up the leaves as follows:

  • leaves 0, 1, 2, 3 and 4 go in the first row
  • leaves 5, 6, 7, 8 and 9 go in the second row

If you have any questions about this please send me an email or leave a comment below.

Best of luck!

Mr. Reitz

Getting Started with WeBWorK

Heads up: if you’re looking for the “Welcome and Getting Started” post that was here before, it now appears farther down the page — just scroll down to see it.

WeBWorK is accessible from on and off campus (anywhere you have access to the internet).  Your first assignment will be due on Thursday, February 14th, and will cover the material from Sections 2.1, 2.2 and 2.3.  Here’s what you have to do:

Assignment.  You must complete the following three steps.

Step 1.  Log in to WeBWorK here:  http://mathww.citytech.cuny.edu/webwork2/MAT1272-Reitz/.  I have created Usernames and Passwords for each student registered for my class.

Username.  Your username for WeBWorK consists of your first initial plus your last name, all lowercase (for example, John Smith would have username ‘jsmith’).

Password.  Your temporary password is the same as your username (if your username is ‘jsmith’, your password is currently ‘jsmith’).

Step 2.  Change your password and update your email address.  To do this, select “Password/Email” from the main menu on the left.  Use whatever email address you like (I suggest using one that you check often).

Step 3.  Complete the first assignment, titled Assignment1 – Sec 2.1-2.3, by clicking on it in the main screen.

If you have any trouble – either with logging in, or with completing the assignment, post a comment here or send me an email and I will get back to you.

WeBWorK Tips:

  1. Click on a problem to see the details (the list of problems appears in the menu on the left).  Enter an answer and hit “Submit Answers”.  Don’t worry, if you get it wrong you can try it again.
  2. If the answer is a number:  you can enter it either as a decimal, like 72.2566 (round your answer), or as an exact answer, like 23*pi.
  3. You can work on the problems in any order you wish.  You can do some problems now, and come back and do the rest another day (your work will be saved, as long as you submit your answers).
  4. If you want to print out a copy of the assignment, click on the assignment name in the main menu on the left, and then click the link in the main screen area that reads “Download a hardcopy of this homework set.”