Four brands of light bulbs are being considered for use in the final assembly area of the Saturn plant in Spring Hill, Tennessee. The director of purchasing asked for samples of 100 from each manufacturer. The numbers of acceptable and unacceptable bulbs from each manufacturer are shown below. At the .05 significance level, is there a difference in the quality of the bulbs?
A B C D
Unacceptable 12 8 5 11
Acceptable 88 92 95 89
Total 100 100 100 100
Uses chi square test to test the hypothesis that there a difference in the quality of the bulbs produced by different manufacturers.