Unformatted text preview: t D,
take independent simple random samples from 2
d x− 2
=1 x
populations Hypothesis Tests Use for
both ◦ use difference between sample means
as the
d x− 2
=1 x
interval
random variable
estimation
d x− 2
=1 x
and ◦ use sampling distribution of
hypothesis if both populations follow normalx x = − n1 and n2 are
E =1 2 µ µ
d −) 1 2
( distribution or if
testing
large enough for Central Limit Theorem to apply, then
σ2 σ 2
will have a normal distribution 2
σ= 1+
d
n n2
1 mean or expected value is Statistical Inference about the Difference
between Two Population Means (σ1 and σ2
known) population sampling parameter: D = μ1– μ2 xx
distribution ofd= 1− 2 Hypothesis Tests Statistical Inference about the Difference
between Two Population Means (σ1 and σ2
known)
Population Mean
μ point estimator x standard error
Hypothesis Tests parameter σx = margin of error zα 2 interval estimate σ
n σ
n x ±z 2
α σ
n Recall from
chapter 8 Statistical Inference about the Difference
between Two Population Means (σ1 and σ2
known)
Population Mean Difference Between 2
Population Means parameter μ D = μ1 – μ2 point estimator x d x− 2
=1 x standard error
Hypothesis Tests margin of error
interval estimate σx =
zα 2 σ
n σ
n x ±z 2
α σ=
d
z2
α σ
n σ2 σ 2
1
2
n
1 + n2 σ2 σ 2
1
2
n
1 d ±z 2
α + n2 σ2 σ 2
1
2
n
1 + n
2 Statistical Inference about the Difference
between Two Population Means (σ1 and σ2
known)
Population Mean Difference Betwee...
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This document was uploaded on 03/05/2014.
 Spring '13

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