Unit Exercise 6
From: Sheik Mahamoodally
Due date: 17 Feb 2020
To: Albert Wong
BUSI 1013 Statistics for Business
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 standarddeviation 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 alarger sample size on the length of the confidence interval at the same confidence level?
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- Winter '15
- Normal Distribution, Standard Deviation, Simple random sample
