Peak expiratory flow (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 conducts a study to investigate whether there is a difference in mean PEF in children with chronic bronchitis as compared to those without asthma or other respiratory conditions often have restricted PEF. Data on PEF are collected and summarized below. Based on the data, is there statistical evidence of a lower mean PEF in children with chronic bronchitis as compared to those without?

Run the appropriate test at = 0.05.

Group Number of Children MeanPEF StdPEF

Chronic Bronchitis 25 281 68

No Bronchitis. 25 319 74