K300 Statistics, Prof. Kruschke

Homework 4, Due at the beginning of class, Tuesday Feb. 15, 2005.

The Excel project (last exercise) will be discussed extensively in class on Thursday Feb 10.

Be sure to

  • write your name and ID on every page
  • make a copy of your homework for your own records and exam study
  • staple (not paper clip) your pages
  • write clearly
  • show your work as appropriate -- an unannotated sequence of numbers and derivations that mysteriously ends up with the correct numerical answer will not be given full credit
  • answer every part of every question (unless instructed otherwise).
    1. 2 pts. Page 180, #12.
    2. 4 pts. Page 180-181, #13, cases (a), (d), (e) and (f) only.
    3. 6 pts. Page 181, #15, cases (a) and (c) only.
    4. 4 pts. Page 182, #19, but do NOT do part (d).
    5. 4 pts. Page 182, #21, but do NOT do part (d).
    6. 5 pts. Rosenberg Excel worksheet 4-2. Work through to the sheet labeled "your data (n=9)".
      • Before following the instructions on that sheet, make the following correction: Notice in cell B18 the formula is =AVERAGE(B9:B17). That is correct; the numbers in row 18 should be the means of the 9 numbers above them. But in all the subsequent columns, the formula is entered incorrectly. For example, in column C the formula in cell C18 is =AVERAGE(C10:C17) but it should be =AVERAGE(C9:C17). To fix this error, select cell B18, then drag the lower right corner of the selection box over all the highlighted cells to its right in row 18.
      • Now follow the instructions on the worksheet, but for the random number seed, use the last four digits of your student ID number.
      • Print just the first page of that sheet (not all 50 columns), so we can see the mean of the sample means and the SD of the sample means.
    7. 15 pts. Excel project: Sampling distribution of the mean. This is much like the Rosenberg spreadsheet in the previous exercise, but laid out differently. Variations of this spreadsheet will be used in future homework assignments. So work carefully on this now to make future assignments easier.
      • Get the spreadsheet from the Oncourse Group Space, "Excel Spreadsheets". The name of the file is K300HW4_SampDistMean_Blank.xls.
      • Carefully follow the directions displayed in the worksheets. Notice that there are five sheets in the workbook. Do all five.
      • Print out one page for each of the four worksheets for which you have to type in formulas or make graphs, so we can see that the columns begin correctly and that the graphs are correct. You might have to use landscape orientation when you print.
      • The worksheets have several "Stop and Think!" questions, numbered consecutively 1-15. Write answers to these questions neatly on a separate page.