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STAT 3022, April 28. 2009
Homework
7
Solutions
TA: Jingfran \,{eng
12.23. (a) With
I
:4
and
N
:2290,
the degrees of freedom are DFG

I

I
:3
and
DFE: N

I
:2286.
(b)MSE:t3:4.6656,so
F:
H#:
*H:2.5304.
(c)The
f
(3, 1000) entry
in Table E gives 0.05
< P <
0.10; sofrware give
p
:0.0555.
1225. (a) The plot suggests
rhat borh drugs
cause an increase in activity level, and
Drug B appears to have a greater
effect.
(b) Yes: The guidelines for pooling
stan
dard deviations say rhat the ratlo
of largest
to smallest should be less
than 2: we have
,C.*
l;f
:
1.4
< 2. The pooled
variance is
_:
.trsi +
t22
+
..+
s{t
149.25
\
:
J',
_
t1r'LJ
_oo<
12
r
) f JtJ+J
f J
t)
and .ro
:
J\95:
3.1544. (c) The degrees
of freedom are DFG
*
I

I
:
4and DFE
:
.y'

1
:
distribution in Table E, we
see that 0.010
<
p
< 0.025;
significant evidence that the means are not
all the
same.
22
_20
0)
o.^

tb
=
o
14
Placebo
Low
A
High
A
Low
B
High B
Treatment
15. (d)
Companng to an F(4,
15)
software gives P
:
0.0156. We have
L2.29. (a)
Table
belou'(x,
s, s; in
rng/100
g)
(b)
To tesr Ho:
pt
:
tL2:
tr3
vs.F1.: not all p1
&r? equal, we
have
F:361.74
with df 4 and 5,
and
p
<
reject the
'ull
h1'pothesis.
Minitab output
below. (c)
plot
below. \\,e conclude
content decreases
oYer time
Condition
i
.tf

l4

f4f
0.000.5, so we
that vitamin
C
Seven
Immediate
One dai'
Three dat,s
Five days
Seven days
C' JU
2n,
o.+u
tr^
an
6"
o20
_ t3
F
1n
(0F
2
2
a
2
2
48.705
41.955
2t.195
\2.415
8.320
I .534
2.128
0.171
l.082
0.269
r .085
r.505
0.s45
0.165
0.190
(a) R codes to compute sampie size,
Irlean, standard devratron and standard error
fcrr
each conclition:
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This note was uploaded on 02/24/2011 for the course STAT 3022 taught by Professor Staff during the Spring '08 term at Minnesota.
 Spring '08
 Staff

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