Brittany Poyer
4/6/07
Melanie 9 am Recitation
Assignment
#10:
1.
The F ratio is significant
because after looking in the chart in the book, with alpha
level .05, the fvalue
needed to be significant was 3.35 our fratio
was 10.88.
2.
The f ratio does not tell us what means are significantly
different
from each other,
it tells us how some means are significant
different, but we are unsure exactly of
which ones.
3.
The means for the three tests:
a.
30 minutes75.60
b.
45 minutes84.70
c.
60 minutes92.40
4.
The three possible mean differences
are the comparisons
between 30 minutes
versus 45 minutes,
30 minutes versus 60 minutes, and 45 minutes versus 60
minutes.
The mean differences
associated with the three comparisons
are:
a.
30 min vs 45 min (75.684.7)=9.1
b.
30 min vs 60 min (92.475.6)=16.8
c.
45 min vs 60 min (84.792.4)=7.7
5.
(31)=2, F value =3.35, Mean square error=64.996,
n=10.
After calculating
the
Scheffe value using the formula in the text, we came up with 9.33.
Any value
greater than 9.33 in this case, would be considered
significant
6.
Using Scheffe, the mean differences
that would be considered
significant
are 30
min and 60 min since the value was 16.8 (greater than 9.33).
The others were less
'" 2.
than 9.33, making them not significant.
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7.
Add the means of 45 min and 30 min (75.6+84.7)
and divide by two to get the
average which was 80.15.
You take 80.15 and subtract it from the 60 minutes
mean (92.480.15)=12.25.
When we compare
12.25 with the Scheffe value, we
found it to be significant
because it was greater than 9.33.
8.
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 Spring '08
 DECKER,MIK
 Statistics, Null hypothesis, Statistical hypothesis testing, Type I and type II errors, Statistical power

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