The quality control department at Food Town Inc., a grocery chain in upstate New York, conducts a monthly check on the comparison of scanned prices to posted prices. The chart below summarizes the results of a sample of 500 items last month. Company management would like to know whether there is any relationship between error rates on regularly priced items and specially priced items.
Regular Price Advertised Special Price
Undercharge 20 10
Overcharge 15 30
Correct Price 200 225