An experiment to determine the efficacy of using 95% ethanol or 20% bleach as a disinfectant in removing bacterial and fungal contamination when culturing plant tissues was repeated 15 times for each disinfectant. The plant tissue being cultured was sweet potato: Five cuttings per plant were placed on a petri dish for each disinfectant and stored at 25 C for 4 weeks. The observation reported was the number of uncontaminated cuttings after the 4-week storage.
a. Is it reasonable to assume that the underlying variances are equal?
______________
b. Are you willing to conclude that there is a significant difference in the mean numbers of uncontaminated eggplants for the two disinfectants tested?
t = ______________
There ______________ evidence of a difference in the mean number of uncontaminated eggplants for the two disinfectants.