In: Statistics and Probability
According to a recent government survey, the daily one-way commuting distance
of U. S. workers averages 13 miles. An investigator wishes to determine whether the
national average describes the mean commute distance for all workers in the Chicago area.
Commute distances are obtained for a random sample of 100 workers from this area, and the
mean distance is found to be 12.25 miles with a standard deviation of 2.5 miles. Test the null
hypothesis at the .05 level of significance.
A. State H 0 : ______________________
B. State H A : ______________________
C. Is this a one- or two-tail test? Why? ______________________________________
D. What is(are) the critical value(s)? ______________________
E. What is the decision rule? _______________________________________________
F. Calculate the t statistic:
t = x̄- µm/ s/√n
G. What is your decision regarding H 0 and why? _______________________________
H. Interpretation of the results: _____________________________________________