The following data represent the price of liquefied natural gasoline (LNG) at self-service stations in four counties in New York City and two suburban counties in a recent week. The data is also included in the Excel spreadsheet Problem C.
Manhattan Bronx Queens Brooklyn Nassau Suffolk
2.339 2.199 2.239 2.259 2.199 2.179
2.299 2.139 2.239 2.199 2.199 2.159
2.239 2.139 2.279 2.359 2.259 2.119
2.299 2.159 2.299 2.259 2.239 2.159
2.319 2.179 2.279 2.319 2.239 2.219
At the .05 level of significance, is there evidence of a difference in the mean price of LNG in the six counties? Which counties are different? Which counties are the best/worst? Perform the appropriate statistical tests.