The monthly closing stock prices (rounded to the nearest dollar) for Panera Bread Co. for the first six months of 2010 are reported in the following table.
Month Closing Stock Price
January 2010..... $71
February 2010..... 73
March 2010..... 76
April 2010..... 78
May 2010..... 81
June 2010..... 75

a. Calculate the sample mean and the sample standard deviation.
b. Compute the 90% confidence interval for the mean stock price of Panera Bread Co., assuming that the stock price is normally distributed.
c. What happens to the margin of error if a higher confidence level is used for the interval estimate?

  • CreatedJanuary 28, 2015
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