Peak expiratory flow PEF is a measure of a patients ability

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 wants to test whether children with chronic bronchitis have restricted PEF. A sample of 40 children with chronic bronchitis are studied and their mean PEF is 279 with a standard deviation of 71. Is there statistical evidence of a lower mean PEF in children with chronic bronchitis? Run the appropriate test at a=0.05.

a.What is the null hypothesis

i.H0 > 306

ii.HO < 306

iii.HO = 306

b.What is the research or alternative hypothesis?

i.H1 >306

ii.H1<306

iii.H1-=306

c.When would we reject HO?

i.When the answer = 0

ii.If the alternative hypothesis is greater

iii.If Z = 1.645

iv.If Z is < or = -1.645

d.Would we reject or accept the HO?

i.Accept

ii.Reject

iii.There is not enough information

Solution

a.) H0=306

b.) H1<306

c.) If Z is <or= -1.645

d.)Z = (306-279)/(71÷40)

= 2.405

Z > 1.645

Therefore we reject H0