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11/15/2019Omodolapo Agbolade-OlasindeUnit 6 ExerciseInstructor: Albert Wong25/28
1.A simple random sample of 80 customers is selected from an account receivable portfolio and the sample mean account balance is $1250. The population standard deviation σ is known to be $250. (8 points)a.Construct a 95% confidence interval for the mean account balance of the population.b.What is the margin of error for estimating the mean account balance at the 95% confidence level.c.Construct a 95% confidence interval for the mean account balance of the population if the sample mean account balance is obtained from a random sample of 150 instead of 80.d.Based on the results from a. and c., what can you say about the effect of a larger sample size on the length of the confidence interval at the same confidence level?