Peak expiratory ]ow (PEF) is a measure of a patient's ability to expel air from the

lungs. Patients with asthma or other respiratory conditions often have restricted

PEF. The mean PEF for children free of asthma is 306. An investigator wants to test

whether children with chronic bronchitis have restricted PEF. A sample of 50

children with chronic bronchitis is studied, and their mean PEF is 251 with a

standard deviation of 71. When you run the appropriate test at a = 0.05, the

appropriate conclusion to whether there statistical evidence of a lower mean PEF in

children with chronic bronchitis is?