The Ohio Department of Highways is in the process of selecting a new paint for highway use. Four different paint companies have been contact regarding this need and each of the companies has supplied paint for testing. Before deciding the winner of the new contract, a test was conducted to determine which paint was the best, in terms of how long it would last. The results of the test are as follows:
Category Paint A Paint B Paint C Paint D
Days 345 320 350 310
Each paint is expected to last 330 days. Is there a significant difference between these four paints? Use the chi square distribution at the .05 significant level to answer this question.
A. Paint B and D are significantly different then paints A and C.
B. The test result is greater than the critical value, so there is a significant difference.
C. A decision cannot be made; more testing is required.
D. The test result is less than the critical value, so there is not a significant difference.
Step by step method for computing test statistic for hi square goodness fit is given in the answers.