Exposure to volatile organic compounds (VOCs) which have been inditified in indo

Question

Exposure to volatile organic compounds (VOCs) which have been inditified in indoor air is suspected as cause for headaches and respiratory symptoms. Indoor plants have not only a positive psychological effects on humans, but may also improve the air qualitity. Certain species of indoor plants were found to be effective removers of VOCs. The following data gives the benzene level (in ppm) in 10 test chambers measured at the beginning of the study and after 3 days, using the plant Epipremnum aureum (Devil's Ivy).

Is there any evidence that these species of indoor plants are effective in removing the benzene from the indoor air? Justifty your answer using a 95% confidence interval and a test hypothesis. Use R-software to verifty that the differences di = xi - yi = 1,...,10 satisfy the normality assumption.

Please, show all work. Thank you in advance.

Initial benze level (xi) Benzene level after 3 days (yi) 28.4 27.4 27.3 26.3 25.5 25.6 29.4 24.5 30.2 28.7 31.3 29.6 28.6 27.5 28.4 28.4 26.5 23.2 27.3 24.3

Explanation / Answer

to test the null hypothesis H0:di = xi - yi=0

first read the variable x and y in R-package as paste the following command which are bold

x=c(28.4,27.3,25.5,29.4,30.2,31.3,28.6,28.4,26.5,27.3)

y=c(27.4,26.3,25.6,24.5,28.7,29.6,27.5,28.4,23.2,24.3)

t.test(x,y,paired=TRUE)

follwoing output will generate

Paired t-test

data: x and y
t = 3.5206, df = 9, p-value = 0.006509
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
0.6219663 2.8580337
sample estimates:
mean of the differences
1.74

since the p-value is less than alpha=0.05 so we reject H0 and conclude that differences di = xi - yi is not zero.

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.