A student decides to investigate how effective washing with soap is in eliminating bacteria. To she tested four different methodswashing with water only, washing with regular soap, washing with antibacterial soap, and spraying hands with antibacterial spray (containing 65% ethanol as an active ingredient). She suspected that the number of bacteria on her hands before washing might vary considerably from day to day. To help even out the effects of those changes, she generated random numbers to determine the order of the four treatments. Each morning she washed her hands according to the treatment randomly chosen. Then she placed her right hand on a sterile media plate designed to encourage bacteria growth. She incubated each plate for 2 days at 36C, after which she counted the bacteria colonies. She replicated this procedure 8 times for each of the four treatments. The data for the bacteria study is given on Canvas. A higher bacteria count means dirtier hands after washing! You may use software when needed. (Hint: Perform an ANOVA analysis)

Treatment Bacteria_Count

Spray 51

Spray 5

Spray 19

Spray 18

Spray 58

Spray 50

Spray 82

Spray 17

AB Soap 70

AB Soap 164

AB Soap 88

AB Soap 111

AB Soap 73

AB Soap 119

AB Soap 20

AB Soap 95

Soap 84

Soap 51

Soap 110

Soap 67

Soap 119

Soap 108

Soap 207

Soap 102

Water 74

Water 135

Water 102

Water 124

Water 105

Water 139

Water 170

Water 87

Question 6: Upload the Normal Quantile Plot (also called Normal Probability Plot) and the Residuals by Predicted Plot.

Question 7: Comment on each of the appropriate assumptions that relate to the two plots you uploaded in Question 6. Discuss whether or not the assumptions are met in context of this problem.

Question 8: The student is now looking for a more detailed answer for this significance test. Conduct a follow-up analysis using both Tukey's and Fisher's methods and upload the Connecting Letters Report software output from both methods.