Hand in Monday (Yes. SPSS is working
in the labs as of Fri. afternoon. Also in the classroom):
Longer,
more detailed version of the
handout for SPSS on two-sample problems here, +
in white folder outside my door
p.423-4, 7.68 Diet--bus conductor's
alcohol parts a and d only! (Reviews one sample t)
Two-sample-- (SPSS problems are marked.
We'll do SPSS first here)
p. 396, 7.30, 7.31 s, SE, d.f. (In 7.31:
the null hypothesis is that there is no difference in the CA/CL, the alternative
is that failed companies will have had a lower CA/CL than healthy--assets
is what you own, liabilities is what you owe. Duh.)
A. (SPSS)
(Mimicking the handout.) Examples 7.7,
7.8, 7.10 in Moore, p.393 ff. Produce (& Hand IN) the output
shown in the handout. Write down the p-value for the test, & the 90%
confidence interval for the difference of means. We'll "always"
use the "equal variances not assumed" option.
Note--If you bring in the data from the
Excel or text file, the "groups" column will have 2's and 16's so you use
2 and 16 as the labels for group 1 and 2. If you use "2" for group
1 and "16" for group 2, it will do (2-week-mean) - (16-week-mean).
It will also allow you to use "16" for group 1 and "2" for group 2--then
it will do (16-week-mean) - (2-week-mean). So (unlike the matched-pairs
situation) you can choose which way to subtract.
(SPSS) p.399
7.32 logging If you type in the data , remember you need all the
tree species numbers in one column, and a "groups" column for logged
or unlogged. (You can use strings or numbers for your logged/unlogged
labels)
7.35 (a) chicks. You can do
this efficiently by hand with a back-to-back stemplot, or use SPSS.
SPSS won't do back-to-back stemplots, but you can get separate stemplots
and side-by-side boxplots, using Analyze>Descriptive Statistics>Explore,
using the plots there. Your response variable goes in the Dependent
list, your groups variable goes in the Factor list.
(SPSS) 7.35
b,c chicks
(SPSS) 7.48
The maze scented/unscented again. Here examine whether learning affects
performance by comparing "unscented first" to "unscented second" (="scented
first").
Reading other output:
p.404, 7.37 (DDT), (read page 404 about
SAS output, compare with our SPSS handout.)
p.406, 7.39 self concept
x x x x x x x x x x x x x x x x x x x x
By hand: These will be optional this term.
p. 401, 7.34 beetles in oats (test)
p. 412, 7.49 voice onset time (test and CI)
= = = = = = = = = = = = = = = = = = = =
= = = = = = = = = =
Due Wednesday: Try SPSS now?
More complicated problems: putting together everything...
Read them over, do what
you can, bring questions ? These are all 2-sample questions; You
may not want to go through the hand computations (7.45, 67, 72) tonight.
ever. But
they are worth reading for the style of presentation of data, what are
the hypotheses, CI's of what.
(SPSS) p. 400, 7.33 Math sublimina. This
is a complicated design: matched pairs, then 2-sample on the differences!
But notice chicks (7.35 ) was also matchedpairs--weight gain =after-before--but
they gave us the pre-subtracted numbers.
p.410, 7.45 fitness Do b. Then
Look in the back at the answers for a and b. (Don't bother to do
the computations yourself)
(SPSS) p.422, 7.63 pasture fertilization
p.423 7.67 London bus people, the rest..
p.425 7.72 reading biology |
.
Not quite t, but close:
0 same as µ1