Estimation of a Confidence Interval for the Diffrence
Prof. M.Vaisfeld
Between Two Population Means with t distribution
May 9'09
α =
0.1
(see handout #11)
Sample 1
Sample 2
15
15
11
7
2
2.5
Pooled estimate (11.4) of the common variance is
5.125
0.82664
28
1.406223
4
1.701131
4
±
1.406223
or
[
2.593777
,
5.406223
]
Estimation of a Confidence Interval for the Diffrence
Between Two Population Means with t distribution
DON'T ENTER ANY DATA IN THE CELLS
A40:D44 !!!
α =
0.1
Sample 1
Sample 2
The cells
A39:D43
display
15
15
the copy of data entered
11
7
in the cells A6:D10 above.
2
2.5
14
1.7613101358
14
1.7613101358
1.7613101
0.82664
1.455969
4
==>
4
±
1.455969
[
2.544031
,
5.455969
]
Enter all numerical data only in the block of cells
A6:D10
(the entered values are copied automatically in the block of cells
A39:D43
below.)
n
1
=
n
2
=
n
1
and n
2
are the sizes of the samples 1 and 2,
x
mean_1
*
=
x
mean_2
*
=
x
mean_1
*
and
x
mean_2
*
are the sample means,
s
1
=
s
2
=
s
1
and s
2
are the sample standard deviations.
A.

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