4. A simple random sample of 300 items is selected from a large shipment, and testing reveals that 4% of the sampled items are defective. The supplier claims that no more than 2% of the items in the shipment are defective. Carry out an appropriate hypothesis test and comment on the credibility of the supplier's claim

5.It has been claimed that 65% of homeowners would prefer to heat with electricity instead of gas. A study finds that 60% of 200 homeowners prefer electric heating to gas. In a two-tail test at 5% level of significance, can we conclude that the percentage who prefer electric heating may differ from 65%.