According to the Bureau of Labor Statistics (1996), the average price of a gallon of gasoline in all US cities in the United States in January 1996 was $1.129. A later random sample in 24 cities found the mean price to be $1.14 with a standard deviation of 0.01. Test at α = 0.05 to see whether the average price of a gallon of gas in the cities had recently changed.