Unit 6 Exercises.docx - Unit6Exercises William(Michael)Turner Professor:GhassemZarbi th Sunday,August16,2018 Unit 6 Exercises 1 a Develop a point

Unit 6 Exercises.docx - Unit6Exercises...

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Unit 6 Exercises William (Michael) Turner BUSI 1013 – Statistics for Business  Professor: Ghassem Zarbi Sunday, August 16     th    , 2018
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Unit 6 Exercises 1. a. Develop a point estimate of the mean number of transactions for the retailer. Point estimate of the mean number of transactions for the retailer is sample mean. Since E sample mean = Population mean Mean number of transaction for the retailer = x = 1298 / 30 = 43.26667 b. Develop a point estimate of the population standard deviation of the number of transactions. The point estimate of the population standard deviation of the number of transactions is: ∑(x – x) 2 / n – 1 = 13.33374 2. a. x = 2.5 / 50 = 0.35355339 z = 3 – 3.4 / 0.35355339 = -1.1314 or -1.13 P(z < -1.13) = 0.1292 b. No assumptions need to be made. The sample size is greater than 30. c. x = 2.5 / 100 = 0.25 z = 3 – 3.4 / 0.25 = -1.6 P(z < =-1.6) = 0.0548 3. a. σ P = √p(1−p) / √n= √.25(1−0.25) / √200=0.0306 b. p 1 = 0.21 p 2 = 0.29 σ p = 0.0306 z 1 = 0.21 0.25 / 0.0306 = 1.31 z 2 = 0.29 0.25 / 0.0306 = 1.31 P(-1.31 < z < 1.31) = 0.9049 – 0.0951 = 0.8098 There’s a 0.8098 chance the sample of 200 customers will have a sample proportion of churn that is ± 0.04 of the population proportion.
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