Question

Do you want to own your own candy store? Wow! With some interest in running your own business and a decent credit rating, you can probably get a bank loan on startup costs for franchises such as Candy Express, The Fudge Company, Karmel Corn, and Rocky Mountain Chocolate Factory. Startup costs (in thousands of dollars) for a random sample of candy stores are given below. Assume that the population of x values has an approximately normal distribution. 92 171 131 92 75 94 116 100 85 (a) Use a calculator with mean and sample standard deviation keys to find the sample mean startup cost x and sample standard deviation s. (Round your answers to one decimal place.) x = thousand dollars s = thousand dollars (b) Find a 90% confidence interval for the population average startup costs μ for candy store franchises. (Round your answers to one decimal place.) lower limit thousand dollars upper limit thousand dollars

Answer 1

( a )

sample mean = 956 / 9 = 106.2

sample standard deviation = sqrt ( ∑(xi−X bar) 2 / ( n -1 ) 0

                                                  = sqrt ( 6923.5556 / 8 )

                                                  = 29.4

( b )

90% confidence interval

lower limit = 88.0

upper limit = 124.4