The Scottsdale fire department

The Scottsdale fire department aims to respond to fire calls in 4 minutes or less, on average. State the hypotheses you would use if you had reason to believe that the fire department’s claim is not being met. Hint: Remember that sample data are used as evidence against the null, not to prove the null is true.

9.8         The average age of a part time seasonal employee at a Vail Resorts ski mountain has historically been 37 years. State the hypotheses one would use to test if this average has decreased since the last season.

9.9         Sketch a diagram of the decision rule for each pair of hypotheses.

a.   H0: μ ≥ 80 versus H1: μ 80

b.   H0: μ = 80 versus H1: μ /= 80

c.   H0: μ ≤ 80 versus H1: μ > 80