The Scottsdale fire department aims to respond to fire calls in 6 minutes or les

Question

The Scottsdale fire department aims to respond to fire calls in 6 minutes or less, on average. Response times are normally distributed with a standard deviation of 1 minute 18 seconds. Would a sample of 18 fire calls with a mean response time of 6 minutes 20 seconds provide sufficient evidence to show that the goal is not being met at = .01?

The Scottsdale fire department aims to respond to fire calls in 6 minutes or less, on average. Response times are normally distributed with a standard deviation of 1 minute 18 seconds. Would a sample of 18 fire calls with a mean response time of 6 minutes 20 seconds provide sufficient evidence to show that the goal is not being met at = .01?

Explanation / Answer

a. H0: µ 6 min vs H1: µ > 6 min, Reject H0 if zcalc > 2.326

6 min 20 sec = 380 secs; 1 min 18 sec = 78 secs
z = (380 - 360)/(78/sqrt(18)) = 1.09

P-value = Pr[Z>1.09] = “=1- NORM.DIST(1.09, 0, 1,TRUE )”
= 0.1379

Fail to reject the null hypothesis

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