Plan for September 2, 1999

  1. Return homework to students
    1. Point out that those who received "0" can still hand in the assignment for a grade.
    2. Note that we are serious about homework. When Mr. Trudell, I, or Mr. Saldanha assign homework we expect you to do it with the intention of handing it in. If we do not ask for it, you will still have put serious thought into the assignment and you will benefit from having done that.
    3. I gave you my email address, my cell phone number, and my home phone number. "Not knowing what to do" is not an excuse!
    4. If you find an assignment to be especially difficult, do the best you can. Handing in nothing is a 0. Handing in an honest attempt is at least 50%.
    5. The root word of "homework" is "home". So, once you walk in the door, NO MORE WORKING ON YOUR HOMEWORK. We often will discuss the homework before you hand it in. You may write notes on your homework in an red pencil or red ink. But you may not change your homework. If this becomes a problem we will simply collect your homework immediately, at the beginning of class.
    6. Have students sign a copy of the homework policy and keep a copy for themselves.
  2. Examine histograms from yesterday’s homework. Ask several students to put theirs on the board.
  3. Collect homework.
  4. Does the size of the population matter as to how variable are the percents we calculate from samples of a given size?
    1. The size of the population does not affect variability amongst percents calculated from samples of a given size, as long as the population is "really big" compared to the sample size (e.g., as long as the population is 10 times as large as the sample).
    2. Even then, samples that are greater than 10% of the population size will tend to have smaller variation than would otherwise be the case for samples of that size taken from a larger population.
    3. But, percents calculated from samples taken from a super huge population will not be any more or less variable than percents calculated from same-sized samples taken from a merely really large population.
  5. We have examined the variability among sample percents calculated from samples of various sizes. Can we predict what fraction of all sample percents will be within a certain range of the population percent, whether or not we know the actual population percent?