document.write( "Question 807553: A group of investors wants to develop a chain of fast-food restaurants. In determining potential costs \n" );
document.write( "for each facility, they must consider, among other expenses, the average monthly electric bill. They \n" );
document.write( "decide to sample some fast-food restaurants currently operating to estimate the monthly cost of \n" );
document.write( "electricity. They want to be 90% confident of their results and want the error of the interval estimate to \n" );
document.write( "be no more than $100. They estimate that such bills range from $600 to $2,500. How large a sample \n" );
document.write( "should they take? \n" );
document.write( "
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