Question

Most air travelers now use e-tickets. Electronic ticketing allows passengers to not worry about a paper ticket, and it costs the airline companies less to handle than paper ticketing. However, in recent times the airlines have received complaints from passengers regarding their e-tickets, particularly when connecting flights and a change of airlines were involved. To investigate the problem, an independent watchdog agency contacted a random sample of 20 airports and collected information on the number of complaints the airport had with e-tickets for the month of March. The information is reported below. 14 14 16 12 12 14 13 16 15 14 12 15 15 14 13 13 12 13 10 13 At the .05 significance level, can the watchdog agency conclude the mean number of complaints per airport is less than 15 per month? Use critical value approach.

Answer 1

Population mean (μ) =15.0 sample size (n) = 20 sample mean (x̄) = ∑(x)/n = 270.0/20 = 13.5 sample standard deviation (s) = sqrt(∑((x-x̄)^2)/(n-1)) = sqrt(43.0/(20-1)) = 1.5044 The null and alternative hypothesis:  Ho :μ = 15.0 H1 :μ < 15.0 Test statistc: to = (x̄-μ)/(s/sqrt(n) =(13.5-15.0)/(1.5044/sqrt(20)) to = -4.4591  The test statistc is -4.4591 level of significance = α = 0.05 Degrees of freedom = n-1= 19 critical value =-1.7291 Decision: a) Based on critical value: Reject Ho, since (test statistic= -4.4591) < (critical = -1.7291) Conclusion: There is sufficent evidence to conclude that mean number of complaints per airport is less than 15 per month at 0.05 level since (p_value = 0.00013) <= (α =0.05)