8.1 Estimation Using Normal

# 5 interval estimation known example find an interval

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Unformatted text preview: xU 2.5% Interval Estimation σ Known Example Find an interval symmetrically distributed around the population mean that includes 95% of the sample means. Sampling distribution: µ= 6; σ = for n = 25 38 x 3 x 2.5% xL 95% μ xU 2.5% Interval Estimation σ Known Example Find an interval symmetrically distributed around the population mean that includes 95% of the sample means. Sampling distribution: µ= 6; σ = for n = 25 38 x 3 x find z-scores for 2.5% and 97.5%: z = ±1.96 2.5% xL 95% xU -1.96 μ 1.96 2.5% Interval Estimation σ Known Example Find an interval symmetrically distributed around the population mean that includes 95% of the sample means. Sampling distribution: µ= 6; σ = for n = 25 38 x 3 x find z-scores for 2.5% and 97.5%: z = ±1.96 find corresponding sample means: x− µ z= σx x 2.5% xL 95% xU -1.96 μ 1.96 2.5% Interval Estimation σ Known Example Find an interval symmetrically distributed around the population mean that includes 95% of the sample means. Sampling distribution: µ= 6; σ = for n = 25 38 x 3 x find z-scores for 2.5% and 97.5%: z = ±1.96 find corresponding sample means: − z = xσ µ x x low tail: er u pper tail: − .96 = x−µ 1 σx 1.96 = x−µ σx Interval Estimation use z values corresponding to 95% 2.5% xL 95% xU -1.96 μ 1.96 2.5% σ Known Example Find an interval symmetrically distributed around the population mean that includes 95% of the sample means. Sampling distribution: µ= 6; σ = for n = 25 38 x 3 x find z-scores for 2.5% and 97.5%: z = ±1.96 2.5% find corresponding sample means: − z = xσ µ x x lower tail : upper tail : Interval Estimation −1.96 = x −µ 3 −5.88 = x − µ 1.96 = x −µ 3 5.88 = x − µ multiply by standard error of 3 xL 95% xU -1.96 μ 1.96 2.5% σ Known Example Find an interval symmetrically distributed around the population mean that includes 95% of the sample means. Sampling distribution: µ= 6; σ = for n = 25 38 x 3 x find z-scores for 2.5% and 97.5%: z = ±1.96 find corresponding sample means: − z = xσ...
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## This document was uploaded on 03/05/2014.

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