Question: By law, the levels of toxic organic compounds in fish are constantly monitored. A technique, called matrix solid-phase dispersion (MSPD), has been developed for chemically extracting trace organic compounds from fish specimens (Chromatographia, March 1995). The MSPD method was tested as follows. Uncontaminated fish fillets were injected with a known amount of toxin. The MSPD method was then used to extract the contaminant and the percentage of the toxic compound recovered was measured. The recovery percentage for n = 5 fish fillets are listed below:

Does the data provide sufficient evidence to indicate that the mean recovery percentage of the toxic compound exceeds 85% using the new MSPD method? Test using 5% level of significance. Report your test results and draw conclusion.