Statistics Ambulance and Fire Department Response Interval Study
Ambulance and Fire Department Response Interval Study
OBJECTIVE: To measure the response intervals of fire departments compared with ambulance services in three urban centers to determine whether defibrillators should be added to fire vehicles.
A prospective sample of 936 tiered calls were collected over a six-month period from March 1, 1994, to August 31, 1994. A matched pairs experimental design compared the response interval of the fire department with that of the ambulance service for each call. A study was undertaken to determine whether fire department personnel should be trained in the use of defibrillators and sent to treat ventricular fibrillation rhythm.
The training of fire department personnel is warranted only if:
Fire truck arrives at the scene on average more than 1 min. sooner than an ambulance;
The frequency of arrival within 8 min. is greater for the fire department.
Cambridge and Kitchener
Because F falls into rejection region, there is enough evidence to infer that the population variances differ.
Waterloo
Because F=0.58 is smaller than F Critical, there is not enough evidence to infer that popultaion variances differ.
The objective is to compare two populations of interval data. The parameter is the difference between two means m1-m2, where
m1 = ambulance mean time
m2 = fire dep. mean time
Because we want to determine whether fire truck arrives at the scene on average more than 1 min. sooner than an ambulance, the alternative hypothesis will specify that m1 is greater than m2: