In a study on the effect of an oral rinse on plaque buildup on teeth, eighteen people whose teeth were thoroughly cleaned and polished were randomly assigned to two groups of nine subjects each. Both groups were assigned to use oral rinses (no brushing) for a 2-week period. Group 1 used a rinse that contained an antiplaque agent. Group 2, the control group, received a similar rinse except that the rinse contained no antiplaque agent. A measure of plaque buildup was recorded at 14 days with means and standard deviations for the two groups shown in the table. Control Group Antiplaque Group Sample Size 9 9 Mean 1.24 0.77 Standard Deviation 0.36 0.36 m use SA T (a) State the null and alternative hypotheses that should be used to test the effectiveness of the antiplaque oral rinse. O Ho: (I41 \"2) = 0 versus Ha: (I41 [42) $ 0 O H0:(;41 \"2) 0 versus Ha:(;41 \"2) = 0 O Ho: (#1 \"2) 0 O Ho: ([41 [42) = 0 versus Ha: (I41 [42) 0 (b) Do the data provide sufficient evidence to indicate that the oral antiplaque rinse is effective? Test using a = 0.05. State the test statistic. (Round your answer to three decimal places.) t = :1 State the rejection region. (If the test is one-tailed, enter NONE for the unused region. Round your answers to three decimal places.) t> t 0.100An experiment was conducted to study the use of 95% ethanol versus 20% bleach as a disinfectant in removing contamination when culturing plant tissues. The experiment was repeated 15 times with each disinfectant, using cuttings of eggplant tissue. The observation reported was the number of uncontaminated eggplant cuttings after a 4-week storage. Disinfectant 95lo Ethanol 20% Bleach Mean 3.74 4.86 Variance 2.78093 0.17142 n 15 15 Pooled va riance 1.47618 IA USE SALT (a) Are you willing to assume that the underlying variances are equal? 0 Yes, the ratio of the larger variance to the smaller variance is less than three. 0 Yes, the ratio of the larger variance to the smaller variance is more than three. 0 No, the ratio of the larger variance to the smaller variance is less than three. 0 No, the ratio of the larger variance to the smaller variance is more than three. 0 It is not possible to check that assumption with the given information. (b) Using the information from part (a), is there evidence of a significant difference in the mean numbers of uncontaminated eggplants for the two disinfectants tested? (Use I41 for 95% ethanol disinfectant and \"2 for 20% bleach disinfectant. Use a = 0.05.) State the null and alternative hypotheses. O Ho: (M1 \"2) = 0 versus Ha: ([41 [42) > O O Ho:(;41 \"2) = 0 versus Ha: (/41 '42) O State the test statistic. (Round your answer to three decimal places.) t = :l State the p-value. O pvalue 0.200 State the conclusion. 0 H0 is rejected. There is sufficient evidence to conclude that there is a signicant difference in the mean numbers of uncontaminated eggplants for the two disinfectants used. 0 H0 is rejected. There is insufficient evidence to conclude that there is a significant difference in the mean numbers of uncontaminated eggplants for the two disinfectants used. 0 H0 is not rejected. There is sufficient evidence to conclude that there is a significant difference in the mean numbers of uncontaminated eggplants for the two disinfectants used. 0 H0 is not rejected. There is insufcient evidence to conclude that there is a significant difference in the mean numbers of uncontaminated eggplants for the two disinfectants used