The government antipollution spokesperson asserts that more than 80% of the plants in the region meet the antipollution standards. An antipollution advocate does not believe the govern- ment claim. She takes a random sample of published data on pollution emission for 64 plants in the area and ?nds that 56 plants meet the pollution standards.
(a) Do the sample data support the government claim at the 5% level of signi?cance?
(b) Would the conclusion change if the sample had been 124, but with the sample proportion of the ?rms meeting the pollution standards the same as before?