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Unformatted text preview: ignificance ◦ Interval Estimation ◦
◦ (1–α) is the confidence coefficient zα 2 is the z value providing an area of α/2 in the upper tail
of the standard normal probability distribution
σ is the population standard deviation
σ is the standard error of the sampling distribution of
mn
ean
zα 2 ◦ σ
n σ
n is the margin of error margin of error is
always found by
multiplying the z value
for 1 tail by the standard
error. Population Mean: σ Known
Interval Estimate of a Population Mean: σ Known
Interval
Estimate
also called
Confidence
Interval x ± margin of error
◦
◦ x is the sample mean
α is the level of significance ◦ Interval Estimation ◦
◦ (1–α) is the confidence coefficient σ
n “We are 95% confident
that the population
mean is between… and
…”” zα 2 is the z value providing an area of α/2 in the upper tail
of the standard normal probability distribution
σ is the population standard deviation
σ is the standard error of the sampling distribution of
mn
ean
zα 2 ◦ x ± zα 2 σ
n is the margin of error Population Mean: σ Known KEY IDEA:
Interval estimate is
the point estimate ± value from
probability distribution
multipliedInterval Estimate
by standard error—
this is a reoccurring formula. of a Population Mean: σ Known x ± margin of error ◦
◦ Interval Estimation ◦
◦ is the sample mean
α is the level of significance
(1–α) is the confidence coefficient zα 2 is the z value providing an area of α/2 in the upper tail
of the standard normal probability distribution
σ is the population standard deviation
σ is the standard error of the sampling distribution of
mn
ean
zα 2 ◦ σ
n x ◦ x ± zα 2 σ
n is the margin of error σ Known Example
If the sample mean is found to be 362.3, find the 95%
confidence interval (i.e., interval estimate) for the population
mean. Interval Estimation σ Known Example
If the sample mean is found to be 362.3, find the 95%
confidence interval (i.e., interval estimate) for the population
mean. Population distribution:
◦ Normal distribution:...
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 Spring '13

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