B what is the margin of error at the 95 confidence

b. What is the margin of error at the 95% confidence level?
2. According to a previous study, check out times at a supermarket are between 3 to 12
minutes (180 to 720 seconds.) A survey involving a random sample of customers of the
supermarket is planned and the first order of business is to decide on an appropriate
sample size. The 95% level of confidence will be used. ( 4 points )
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BUSI1013 PAMELLA MITCHELL
UNIT 6 EXERCISE MAY 17, 2019
a. What is the planning value for the population standard deviation to be used in
the sample size formula for estimating the population mean check-out time?
b. How large should the sample size be if the desired margin of error is 25
seconds?
2.
Use the data in BUSI1013 Bank Dataset.xlsx (from Unit 1 Exercise Question 2) to answer
this question. ( 4 points )
a. Construct a 95% confidence interval to estimate the proportion of customers
who would recommend the Bank to family and friends after the change.
b. What is the margin of error of the estimate at the 95% confidence level?
2. In a survey, the planning value for the population proportion is p* = 0.28. How large
should the sample size for the survey be if the desired level of confidence is 95% and the
desired margin of error is 0.035? ( 2 points )
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