A certain chemical pollutant in the Genesee River has been polluted for many years and mean pollution was 34 ppm (parts per million) and population standard deviation σ= 8 ppm. The population standard...

A certain chemical pollutant in the Genesee River has been polluted for many years and mean
pollution was 34 ppm (parts per million) and population standard deviation σ= 8 ppm. The
population standard deviation is skewed to the left. A group of factory representatives whose
companies discharge liquids into the river is saying that they have lowered the average with
improved filtration devices. Test if the pollution remains same or not at 4% level of significance.
Assume that their sample size of 50 gives a mean of 32.5 ppm. Perform a hypothesis test at the
4% level of significance and using critical value approach state your decision. (Draw graph).