Traditionally 25 of customers of a certain cell phone company leave after their

Traditionally 25 of customers of a certain cell phone

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3.Traditionally, 25% of customers of a certain cell phone company leave after their term contract expires. Assume this is the true population proportion of churn (customers leaving after their term expired) and answer the following questions: (6 Points)a.If simple random samples of 200 customers are taken from the population of customers of this company, describe the sampling distribution of the sample proportion of churn. b.What is the probability that a simple random sample of 200 customers will have a sample proportion of churn that is within ± 0.04 of the population proportion?  c.Check the condition for using the normal distribution to approximate the sampling distribution of the sample proportion and see whether it is valid.  1
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Courtney Young- Unit 6 4. A simple random sample of 100 items is taken from an inventory and the average unit cost on the items is $25.5. The population standard deviation   is known to be $10.25. (8 Points)a.Construct a 95% confidence interval for the mean unit cost of the population23.491,27.509b.What is the margin of error at the 90% confidence level? σ
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