p-value math stat

A certain chemical pollutant in the Ohio River has been constant for several years with mean μ = 34 ppm (parts per million) and standard deviation σ = 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. To Perform a hypothesis test the below two hypotheses were stated.  

μ = The population average of chemical pollutant  

Run a hypothesis test using a TI 83/TI 84.  

a. Obtain the p-value.  

b. Give the conclusion