In: Economics
A Bloomberg BusinessWeek subscriber study asked, "In
the past 12 months, when traveling for business, what type of
airline ticket did you purchase most often?" A second question
asked if the type of airline ticket purchased most often was for
domestic or international travel. Sample data obtained are shown in
the following table.
Type of Flight | ||
Type of Ticket | Domestic | International |
First Class | 24 | 29 |
Business Class | 121 | 98 |
Economy Class | 131 | 517 |
a. Using a .05 level of significance, is the type of ticket purchased independent of the type of flight? Use Table 12.4.
H 0: - Select your answer -Type of ticket purchased is independent of the type of flightType of ticket purchased is not independent of the type of flightItem 1
H a: - Select your answer -Type of ticket
purchased is independent of the type of flightType of ticket
purchased is not independent of the type of flightItem 2
Compute the value of the 2 test statistic (to
2 decimals).
The p-value is Selectless than .005between .005 and
.01between .01 and .025between .025 and .05between .05 and
.10greater than .10Item 4 .
What is your conclusion?
Chi-squared test
Type of Flight |
|||
Type of Ticket |
Domestic |
International |
Total |
First Class |
24 |
29 |
53 |
Business Class |
121 |
98 |
219 |
Economy Class |
131 |
517 |
648 |
Total |
276 |
644 |
920 |
H0: Type of ticket and type of flight are independent
H1: Type of ticket and type of flight are associated
Expected Number (E) (assuming that H0 is true) |
Observed Number (O) |
(O-E)2/E |
|
First Class & Domestic |
(53×276)/920 = 15.9 |
24 |
4.13 |
Business Class & Domestic |
(219×276)/920 = 65.7 |
121 |
46.55 |
Economy Class & Domestic |
(648×276)/920 = 194 |
131 |
20.68 |
First Class & International |
(53×644)/920 = 37.1 |
29 |
1.77 |
Business Class & International |
(219×644)/920 = 153.3 |
98 |
19.95 |
Economy Class & International |
(648×644)/920 = 453.6 |
517 |
8.86 |
Total |
920 |
920 |
101.93 |
Chi-square statistics (calculated) = 101.93
Degree of freedom (df)= (number of rows-1) (number of columns-1) = (3-1) (2-1) = 2
We shall accept the H0 if Chi-square (calculated) is smaller than Chi-square table value at given significance level and df=2 and reject H0 (or accept H1) if Chi-square (calculated) is greater than Chi-square table value at given significance level and df=2.
Chi-squared table value at df=2 and .05 significance level= 7.38
Thus, we shall reject H0 (i.e. accept H1) and conclude that the type of ticket and type of flight are associated.
Since the Chi-square statistics (calculated) is greater than 10.597, the results are significant at .005 level of significance.