Local county officials have heard reports that a service station is allowing cars 20 years and older with known violations to pass their annual safety inspection. From administrative data, they know 30% of all cars 20 years and older do not pass their annual safety inspection. To test their theory about the service station, they request records from the most recent 150 inspections of cars of this type, finding 30 of the 150 had been rejected. Let p be the true rate of cars 20 years and older that do not pass their annual safety inspection from this service station. What are the implied null and alternative hypotheses local county officials are testing? Assuming the true value of p is 0.3, which expression is the correct way to compute a test statistic for the proportion observed in the sample?