Chapter 13: Inferential Statistics and Distributions
235
2-SampFTest
2-Samp
Ü
Test
(two-sample
Ü
-test; item
E
) computes an
Ü
-test to compare two normal population
standard deviations (
s
1
and
s
2
). The population means and standard deviations are all unknown.
2-Samp
Ü
Test
, which uses the ratio of sample variances Sx1
2
/Sx2
2
, tests the null hypothesis
H
0
:
s
1
=
s
2
against one of the alternatives below.
•
H
a
:
s
1
ƒs
2
(
s
1:
ƒs
2
)
•
H
a
:
s
1
<
s
2
(
s
1:<
s
2
)
•
H
a
:
s
1
>
s
2
(
s
1:>
s
2
)
In the example:
SAMP4=
{7,
L
4, 18, 17,
L
3,
L
5, 1, 10, 11,
L
2}
SAMP5={
L
1, 12,
L
1,
L
3, 3,
L
5, 5, 2,
L
11,
L
1,
L
3}
Data
Stats
Input:
Calculated
results:
Drawn results:
