Exhibit 9-4

question 48

Multiple Choice

Exhibit 9-4.A school teacher is worried that the concentration of dangerous,cancer-causing radon gas in her classroom is greater than the safe level of 4pCi/L.The school samples the air for 36 days and finds an average concentration of 4.4pCi/L with a standard deviation of 1pCi/L. Refer to Exhibit 9-4.In order to test whether the average level of radon gas is greater than the safe level,the appropriate hypotheses are ____________.