Question

Is the transportation mode used to ship goods independent of type of industry? Suppose the following contingency table represents frequency counts of types of transportation used by the publishing and the computer hardware industries. Analyze the data by using the chi-square test of independence to determine whether type of industry is independent of transportation mode. Let α = 0.05.

Transportation Mode

Industry

	Air	Train	Truck
Publishing	34	12	36
Computer Hardware	5	6	24

Appendix A Statistical Tables

(Round the intermediate values to 2 decimal places. Round your answer to 2 decimal places.)

Observed χ2 =  
Transportation mode is                                                           independentnot independent of industry.

Answer 1

Applying chi square test of independence:

Expected	Ei=row total*column total/grand total	Freshman	Sophomore	Senior	Total
	Publishing	27.33	12.62	42.05	82
	Computer hardware	11.67	5.38	17.95	35
	total	39	18	60	117
chi square    χ2	=(Oi-Ei)2/Ei	Freshman	Sophomore	Senior	Total
	Publishing	1.630	0.030	0.870	2.5300
	Computer hardware	3.810	0.070	2.040	5.9200
	total	5.4400	0.1000	2.9100	8.4500
Observed test statistic X2 =		8.450

p value =

0.0146

since p value <0.05

Transportation mode is not independent of industry.