| Hand in Friday . Matched pairs, and robustness (by hand) p. 455, 18.37 measuring placebo effect Use Table C. You can check with the Excel t-procedures p. 450, 18.14 Reading scores Use Table C. Also, what IS the standard deviation? You can check with the Excel t-procedures--plug in the sample size and what you think is the s.d. and see if you get the given SE . Also , you may find that the mean is (statistically) significantly below the basic level. Is the difference large enough to be important? (I don't know...) p. 455, 18.36b calcium/blood pressure conditions. = = = = = = = = = = = = = = = = = = = = = = Reading SPSS for one-sample procedures: For all these, Use the Handout , which has all the SPSS output for these problems. p. 453, 18.27 Sharks The P-value is better than the .05 level mentioned. What is it (rounded to 3 decimal places)? p. 457, 18.41 Auto crankshafts Matched pairs, and robustness p. 454, 18.34 growing trees faster. Find the differences by hand. p. 446, 18.11and 12 newts healing. These are the rates of healing: the control is supposed to be faster than the experiment, so to get generally positive differences, you would take (ctrl - expt). But SPSS does (expt-ctrl), no choice! Make a stemplot by hand. Read the rest of your needed info off the handout, where I used the "Paired Sample" method." p. 448, 18.13 newts with outlier A dotplot is given on the handout, so you don't need to do a stemplot.. = = = = = = = = = = = = = = = = = = = = = = + + + + + + + + + + + Chapter 19 problems, with echos of Chapters 8 and 9. Note that we can use the same analysis method whether data is from a sample (Example 19.1b) or an experiment (Example 19.1 a, c) or an observational study. p. 461, 19.1, 2, 3, 4. For each, after deciding which design it is, tell if the data comes from a sample, an observational study, or an experiment. |
Read, to discuss |
Optional Using SPSS for one-sample procedures (with SPSS Handout) A. Redo the example on the front page of the handout, getting the result of example 18.3 B. The inclass example of Milk bacteria: (Day 40)do it on SPSS: Dataset as SPSS file, Dataset as text (.dat) file (If you import from the text file, remember to check that the Measure is Scale) C. Redo the results on the back page of the handout, getting the results of example 18.4. Datasets in SPSS for HW problems, if you want to do them yourself: Sharks18-27.sav Crankshafts18-41.sav Trees18-34.sav Newts18-11.sav NewtswithOutlier18-13.sav |
Ch. 18: Inference for population mean
(realistic) continued
What is the
significance
to Statistics of the Guinness Stout Bottle ?
Homework
questions? Day 40
Get Handout
for SPSS Ch. 18
Look at output, decipher it. What SPSS calls
"Sig. (2-tailed)" = "2-sided P-value"
Get Handout of SPSS results to use for HW
See Day 40 for notes
: Matched pairs, Robustness of t-procedures
If you can't do t-procedures, there are
procedures involving medians, or other approaches (Ch. 26)
Another situation which uses
t-statistics is the one in
Chapter 19
"Two-sample problems".
Two random samples, independent of each
other,
from distinct populations. (Populations are normally
distributed)
Often--comparing means from an experiment with two treatments (usually
"control" and "treatment").
/--- Group 1, n1---- Treatment 1---\
/
\
Random
asst.(?)
Compare results --"means"
\
/
\--- Group 2, n2---- Treatment 2---/
To examine the difference of the two means, µ1
- µ2, we look at the difference of the xbars.
We need the Standard Error of the difference xbar1
- xbar2
,
and then we can proceed as before, more or less (with some
adjustments.)
But we've run out of time....
| Sievers home | Math151-Sp07/Daysp41.htm | 11am | 5/9/07 |