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Unformatted text preview: − µ If sample mean
is known, use to
find a range for
the population
mean: x ± 5.88 xL 2.5% 95% xU 2.5% 1.96 μ 1.96 1.96 = x −µ
3
5.88 = x − µ sampling error—difference between
sample mean and population mean Margin of error found by
multiplying the standard error by
the z value. 5.88 is the
margin of
error Population Mean: σ Known
Interval Estimate 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 Population Mean: σ Known
Interval Estimate of a Population Mean: σ Known
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 α is the percent
remaining in
upper and lower
tails 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
Interval Estimate of a Population Mean: σ Known
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 divide α by 2 to
find area in each
tail 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
Interval Estimate of a Population Mean: σ Known x ± zα 2 x ± margin of error
◦
◦ x is the sample mean
α is the level of s...
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This document was uploaded on 03/05/2014.
 Spring '13

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