6.6.9 Some soap manufacturers sell special "antibac- terial" soaps. However, one might expect ordinary soap to also kill

Post by **answerhappygod** » Tue Jul 12, 2022 11:32 am

: 6 6 9 Some Soap Manufacturers Sell Special Antibac Terial Soaps However One Might Expect Ordinary Soap To Also Kill 1 (77.5 KiB) Viewed 49 times

6.6.9 Some soap manufacturers sell special "antibac- terial" soaps. However, one might expect ordinary soap to also kill bacteria. To investigate this, a researcher prepared a solution from ordinary, nonanti- biotic soap and a control solution of sterile water. The two solutions were placed onto petri dishes and E. coli bacteria were added. The dishes were incubated for 24 hours and the number of bacteria colonies on each dish were counted.39 The data are given in the follow- ing table. n Control (Group I) 30 36 66 21 63 38 35 45 8 7 41.8 32.4 15.6 22.8 5.5 8.6 Compute the standard error of (Y₁ - Y₂) for these data. S SE Soap (Group 2) 76 27 16 30 26 46 6

QUESTION 2 Using the data from exercise 6.6.9 on page 211 of the text, interpret the 90% confidence interval for the difference in mean number of bacteria colonies in the soap versus control group. Let H1 denote the mean number of bacteria colonies for the soap population and u2 the same, but for the control group. O A We are 90% confident that the mean number of bacteria colonies for soap is larger than the mean number of bacteria colonies for sterile water by as much as 27.82 colonies or as little as 9.18 colonies. O B. We are 90% confident that the mean number of bacteria colonies for sterile water is larger than the mean number of bacteria colonies for soap by as much as 27.82 colonies or as little as 9.18 colonies. O C. With 90% confidence, we are uncertain which population's mean number f bacteria colonies is larger. If the mean number of bacteria colonies is highest for soap, it is by as much as 9.18 colonies. If the mean number of colonies is highest for sterile water, it is by as much as 27.82 colonies. QUESTION 3 Investigators expect the mean number of bacteria colonies to be lower in the soap condition than in the control group. Test this hypothesis at a 0.10 level of significance. Use the data from exercise 6.6.9 on page 211 of the text and let μ₁ denote the mean number of bacteria colonies for the soap population. Let μ2 be the same, but for the control group. Specify the appropriate hypotheses being tested. OAH, versus H₁₁=₂ versus H="₁=₂ OBH ₁ 1<H₂' OCH ₁₂ = ₂ OD.H₂H₁₂=²₂ QUESTION 4 versus H:₁₂ versus H:₁₂<H₂ Investigators expect the mean number of bacteria colonies to be lower in the soap condition than in the control group. Test this hypothesis at a 0.10 level of significance. Use the data from exercise 6.6.9 on page 211 of the text and let μ₁ denote the mean number of bacteria colonies for the soap population. Let µ2 be the same, but for the control group. Using R to analyze the data, State the conclusion. O A With a p-value of 0.1918 and a significance level of 0.10, we reject the null hypothesis. There is statistically significant evidence to suggest the mean number of bacteria colonies is lower for soap usage than for sterile water. OB. With a p-value of 0.1918 and a significance level of 0.10, we fail to reject the null hypothesis. There is not statistically significant evidence to suggest the mean number of bacteria colonies is lower for soap usage than for sterile water. O C. With a p-value of 0.1918 and a significance level of 0.10, we are unsure if we should reject the null hypothesis. There may or may not be statistically significant evidence to suggest the mean number of bacteria colonies lower for soap usage than for sterile water.