Question

E. Coli bacteria were added to 15 petri dishes and they were incubated for 24 hours. The “soap” dishes contained a solution prepared from ordinary soap; the “control” dishes contained a solution of sterile water. The number of bacteria colonies present in each dish after 24 hours are given below:Soap: 76 27 16 30 26 46 6Control: 30 36 66 21 63 38 35 45The numbers of bacteria colonies in the soap dishes come from a normal distribution with mean μ1 and variance .?21The numbers of bacteria colonies in the control dishes come from a normal distribution with mean μ2 and variance .?22

a. Perform the equality of variances test at 10% significance level. Give hypotheses, test statistic, P-value, conclusion, and interpretation.

b. Perform the appropriate test at the 5% significance level to determine if dishes with soap have lower mean bacteria levels. Give hypotheses, test statistic, P-value, conclusion, and interpretat

Answer 1

calculate mean and standard deviation

for soap(1)

for control(2)

F test for equality of variances

T test for two means