Fall, 2007
MAT
222
Final
(December
12,
2007)
Nanle:
______________________________________
___
***************
1.
There are 7 problems
and
a
total
of 9 pages in this booklet.
2.
Show all of your work
and
label your answers clearly.
3.
If
you use a table,
state
the
table used: for example 1.887 (from Table A).
4.
If
you use a function on
the
TI
83
(or
TI
89), write
out
the
command you entered as well as
the
result: for example, 0.0668 (normalcdf (10, 1.5, 0.1)).
***************
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1
1.
(15
pts)
Students
in a statistics class were asked
the
question: How
many
hours
typically exercise in a week?
The
following
summary
statistics
are obtained:
(a) At
the
5% level of significance,
conduct
a
test
to
determine if
the
mean
exercise differs for men
and
women.
(b) Cheek if each of
the
following
statements
is
true
for
the
test
in (a).
Explain
not.
(i)
We
are
assuming
the
population variances
are
equal for
the
two populations in
study.
(ii)
"11" is
an
appropriate
degrees of freedom.
(iii)
If
MINITAB is used
to
analyze
this
data,
the
degrees of freedom could
be
number.
(iv)
If
the
alternative hypothesis is
that
males exercise more
than
females,
the
be
significant
at
0.05 level of significance.
do
you
amount
of
why or why
the
a decimal
test
will
2
2.
(14 pts) This Washington Post poll
was
conducted by telephone during October 48, 2007
for a random sample of 1,144 adults in
the
Commonwealth of Virginia. For
the
question,
"Regardless of who you may support, which of
the
Democratic candidates do you
think
the
best chance of getting elected president in November 2008?",
the
following summary
results are obtained.
I
Candidate of choice
Political
Party
Democrats Non Democrats
H.
Clinton
B.
Obama
Others
328
76
100
324
130
186
Analyze
the
twoway table.
State
the
hypotheses, calculate
the
X
2
statistic, degrees of free
dom, Pvalue and your conclusion.
has

3
3.
(17 pts) In
the
poll conducted for
the
504 Democrats in
the
Commonwealth of Virginia,
49%
of
the
respondents said
that
they would vote for Hillary Clinton if
the
2008 Democratic
presidential primary or caucus in their
state
were being held today.
(a) Find a
99%
confidence interval for
the
proportion of Democrats in
the
Commonwealth
of Virginia who support Hillary Clinton.
(b) Based
on
your confidence interval in (a), can you conclude
that
the
proportion of Virginia
Democrats who
support
Hillary Clinton is not significantly different from 0.5? Explain
why or why not.
(c) Do
data
provide good evidence
that
the
proportion of supporters of Hillary Clinton in
Virginia is significantly lower
than
53% observed in a national survey conducted about
a month ago?
Find
the
Pvalue of
the
test
and
draw
the
conclusion
at
0.01 level of
significance.
4