In: Statistics and Probability
A market researcher for an automobile company suspects differences in preferred color between male and female buyers. Advertisements targeted to different groups should take such differences into account, if they exist. The researcher examines the most recent sales information of a particular car that comes in three colors. Use Table 3. |
Gender of Automobile Buyer | ||
Color | Male | Female |
Silver | 490 | 298 |
Black | 537 | 290 |
Red | 492 | 348 |
a. | Choose the competing hypotheses to determine whether color preference depends on gender. | ||||
|
b. | Find the critical value at the 1.0% significance level. (Round your answer to 2 decimal places.) |
Critical value |
c. | Calculate the value of the test statistic. (Round the intermediate calculations to at least 4 decimal places and final answer to 2 decimal places.) |
Test statistic |
a)H0: Color preference is independent of gender; HA: Color preference is dependent on gender.
b)
degree of freedom =(row-1)*(column-1)=(2-1)*(3-1)=2
for 2 df and 0.01 level ; critical value =9.21
c)
applying chi square test:
Observed | OBS | silver | black | red | Total |
male | 490 | 537 | 492 | 1519 | |
female | 298 | 290 | 348 | 936 | |
Total | 788 | 827 | 840 | 2455 | |
Expected | Ei=?row*?column/?total | silver | black | red | Total |
male | 487.565 | 511.696 | 519.739 | 1519 | |
female | 300.435 | 315.304 | 320.261 | 936 | |
Total | 788 | 827 | 840 | 2455 | |
chi square | =(Oi-Ei)2/Ei | silver | black | red | Total |
male | 0.01 | 1.25 | 1.48 | 2.74 | |
female | 0.02 | 2.031 | 2.403 | 4.45 | |
Total | 0.03 | 3.28 | 3.88 | 7.197 |
Test statistic =7.20