Four brands of lightbulbs are being considered for use in the final assembly area of Ford F-150 truck plant in Dearborn, Michigan. The director of purchasing asked for samples of 100 from each manufacturer. The numbers of acceptable and unacceptable bulbs from each manufacturer are show below. At the .05 significance level, is there a difference in the quality of the bulbs? Solution 100.00 100.00 100.00 100.00 400.00 Expected A B C D Unacceptable 9.00 9.00 9.00 9.00 36.00 Acceptable 91.00 91.00 91.00 91.00 364.00 100.00 100.00 100.00 100.00 400.00 Caluclation A B C D Unacceptable 1.00 0.11 1.78 0.44 3.33 Acceptable 0.10 0.01 0.18 0.04 0.33 1.10 0.12 1.95 0.49 3.66 The chi-square statistics is 3.66 While critical value=chi_square(0.05,3)=7.815 Since statistics value is less than critical value, we can not reject null hypothesis. Conclusion: there is no difference in the quality of the bulbs..

1. Four brands of lightbulbs are being considered for use in the final assembly area of Ford F-150
truck plant in Dearborn, Michigan. The director of purchasing asked for samples of 100 from
each manufacturer. The numbers of acceptable and unacceptable bulbs from each manufacturer
are show below. At the .05 significance level, is there a difference in the quality of the bulbs?
Solution
100.00 100.00 100.00 100.00 400.00 Expected A B C D Unacceptable 9.00 9.00
9.00 9.00 36.00 Acceptable 91.00 91.00 91.00 91.00 364.00 100.00 100.00 100.00 100.00 400.00
Caluclation A B C D Unacceptable 1.00 0.11 1.78 0.44 3.33 Acceptable 0.10 0.01 0.18 0.04 0.33
1.10 0.12 1.95 0.49 3.66 The chi-square statistics is 3.66 While critical
value=chi_square(0.05,3)=7.815 Since statistics value is less than critical value, we can not
reject null hypothesis. Conclusion: there is no difference in the quality of the bulbs.