MGMT305-Lec5

2 n x whereisthesamplemean

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Unformatted text preview: 2 σ n x where: is the sample mean 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 n is the sample size Slide 7 σ s Known : Interval Estimate of a μ Known : Interval Estimate of a Assume Normal Population Small­Sample (n < 30) x ± zα / 2 σ n x where: is the sample mean 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 n is the sample size NOTE: If the population is not normal – then you will have to increase the sample size to n ≥ 30. Slide 8 σ s Unknown : Interval Estimate of a μ Unknown : Interval Estimate of a Assume Normal Population Large­Sample (n ≥ 30) In most applications the value of the population standard deviation is unknown. In this regard, we could either one of the expressions using the value of the sample standard deviation, s, as the point estimate of the population standard deviation. x ± zα / 2 s n OR x ± tα /2 s n NOTE: You can use either Z or t distribution NOTE: Slide 9 σ s Unknown : Interval Estimate of a μ Unknown : Interval Estimate of a Assume Normal Population Small­Sample (n < 30) • The appropriat...
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