Statistics 102 – Fall 2011
Homework 1 Solutions (10 Questions Total – 1 Point Each)
Problem 2.25:
With JMP, we can compute that the sample mean
=28.15 and the standard deviation is
s
=6.53, and thus
the 95% CI of the mean miles per gallon is
Problem 2.30:
H
0
:
µ
≤
27.5
H
a
:
µ
>
27.5
Decision Rule: Reject
if
, do not reject if
Test statistic:
Decision: Do not reject
.
We do not have enough evidence to conclude that the CAFE standard is being met under the 5% level of
significance.
Problem 2.28,
H0:
µ
≥
5
H1:
µ
< 5
Decision Rule: Reject
if
, do not reject if
Test statistic:
Decision: Reject
.
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View Full DocumentUnder the 5% level of significance, the FTC has grounds to proceed against the manufacturer for the
unfair practice of shortweight selling.
Problem 2.32:
Since
, we can
Assume that the two groups’ GMAT scores have the same standard
deviation, then
So the 95% CI of the difference between the mean GMAT scores is
Problem 2.35:
(1)
If using the unpooled procedure the result of JMP is
t Test
No LoadLoad
Assuming unequal variances
Difference
5.063
t Ratio
1.121621
Std Err Dif
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 Spring '08
 SHAMAN
 Statistics, Standard Deviation, Std Err Dif, Lower CL Dif, CL Dif

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