A certain chemical pollutant in the Genesee River has been constant for several years with mean = 34 ppm (parts per million) and standard deviation is 8 ppm. A group of factory representatives whose companies discharge liquids into the river is now claiming that they have lowered the average with improved filtration devices. A group of environmentalists will test to see if this is true at the 4% level of significance. Assume that their sample of size 50 gives a mean of 32.5 ppm. Perform a hypothesis test at the 4% level of significance and state your decision