Question 1
A group of investors wants to develop a chain of fast-food restaurants . In determining potential costs for each facility , they must consider , among other expenses , the average monthly electric bill . They decide to sample some fast-food restaurants currently operating to estimate the monthly cost of electricity . They want to be 90 % confident of their results and want the error of the interval estimate to be no more than $ 100 . They estimate that such bills range from $ 600 to $ 2,500 . How large a sample should they take ?
Question 2
Suppose a study reports that the average price for a gallon of selfserve regular unleaded gasoline is $ 3.16 . You believe that thefigure is higher in your area of the country . You decide to test this claim for your part of the United States by randomly calling gasoline stations . Your random survey of 25 stations produces the following prices ( all in $). Assume gasoline prices for a region are normally distributed . Do the data you obtained provide enough evidence to reject the claim ? Use a 1 % level of significance .
3.27 3.29 3.20 3.23 3.16 3.07 3.15 3.23 3.21 3.14 Question 3
3.16 3.20 3.37 3.19 3.20 3.24 3.27 3.09 3.35 3.14 3.05 3.35 3.14 3.07 3.10
Where do CFOs get their money news ? According to Robert Half International , 47 % get their money news from newspapers , 15 % get it from communication / colleagues , 12 % get it from television , 11 % from the Internet , 9 % from magazines , 5 % from radio , and 1 % do