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Unformatted text preview: nd 28 J cars (from Japan)
were road tested to compare
mpg performance. The sample
statistics are:
M Cars
Hypothesis Tests n
x
s J Cars 24 28 29.8 27.3 2.56 1.81 Difference Between 2
Population Means
parameter
point
estimate
standard
error DM–J = μM – μJ
d x −J= 5
=M x 2
. s 2 s2
s = M + J =06 5
.2
d
n
n
M
J margin of
error
interval
estimate tα 2 s 2 s22
1
+
n n2
1
s2 s22
1
+
nn
1
2 d ±tα 2 degrees of df =
freedom (+ )
( )+ ( )
s2
1
n1 s2
1
1
n1 − n1
1 2 s22
n2 2 s22
1
n2 − n2
1 2 Example Given these samples, what is the
margin of error for 90% confidence of
the difference between the 2 population
means? Specific Motors of Detroit has
developed a new automobile
known as the M car. 24 M cars
and 28 J cars (from Japan)
were road tested to compare
need the
mpg performance. The sample
degrees of
statistics are: Hypothesis Tests freedom to use
M
the t Cars J Cars
n
24
28
distribution
x
s 29.8
2.56 27.3
1.81 Difference Between 2
Population Means
parameter
point
estimate
standard
error DM–J = μM – μJ
d x −J= 5
=M x 2
. s 2 s2
s = M + J =06 5
.2
d
n
n
M
J margin of
error
interval
estimate tα 2 s 2 s22
1
+
n n2
1
s2 s22
1
+
nn
1
2 d ±tα 2 degrees of
df =
freedom (+ )
( )+ ( )
s2
1
n1 s2
1
1
n1 − n1
1 2 s22
n2 2 s22
1
n2 − n2
1 2 Given these samples, what is the
margin of error for 90% confidence of
the difference between the 2 population
means? Example Difference Between 2
Population Means Specific Motors of Detroit has
developed a new automobile
known as the M car. 24 M cars
and 28 J cars (from Japan)
were road tested to compare
need the
need the
mpg performance. The sample
degrees of
statistics are: of
degrees Hypothesis Tests freedom to use
freedom to use
M
the t Cars J Cars
the t 24
n
distribution s 28+ s
distribution (n n
x
29.8
27.3
2 M df = s 2.56 = J M 1
nM 2
J parameter
point
estimate
standard
error )
2 ( 1.81+ ( )
) sM 2
−1 n M 2 sJ 2
1
n J −1 n J 2 (+)
( )+ ( )
2.56 2
24 1
2.56 2
24 −1
24 1.812
28 2 = 40.58 ≈ 40 2 1
1.812
28 −1
28 2 DM–J = μM – μJ
d x −J= 5
=M x 2
. s 2 s2
s = M + J =06 5
.2
d
n
n
M
J margin of
error
interval
estimate tα 2 s 2 s22
1
+
n n2
1
s2 s22
1
+
nn
1
2 d ±tα 2 degrees of df =
freedom (+ )
( )+ ( )
s2
1
n1 s2
1
1
n1 − n1
1 2 s22
n2 2 s22
1
n2 − n2
1 2 Example Given these samples, what is the
margin of error for 90% confidence of
the difference between the 2 population
means? Specific Motors of Detroit has
developed a new automobile
known as the M car. 24 M cars
and 28 J cars (from Japan)
s1 2
s2 2
tα 2 n1 + 2
were road testedn to compare
mpg performance. The sample
sM 2
sJ 2
= 10 2
statisticst.are: n M + n J Hypothesis Tests = t.M 2Cars
10 ⋅ 0 . 625 J Cars
n = 1 . 684 ⋅ 0 .625 28
24
x = 1 . 053
29.8
27.3
s 2.56 1.81 Difference Between 2
Population Means
DM–J = μM – μJ parameter
point
estimate
standard
error d x −J= 5
=M x 2
. s 2 s2
s = M + J =06 5
.2
d
n
n
M
J margin of
error
interval
estimate
degrees of df =
freedom tα 2 s 2 s22
1
+
n n2
1
s2 s22
1
+
nn
1
2 d ±tα 2 ( + ) ≈40
( )+ ( )
sM2
nM sM2
1
nM − nM
1 2 sJ 2
nJ 2 sJ 2
1
nJ − nJ
1 2 Example Given these samples, what is the...
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This document was uploaded on 03/05/2014.
 Spring '13

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