One of the factors that determine the degree of risk a pesticide poses to human

Question

One of the factors that determine the degree of risk a pesticide poses to human health is the rate at which the pesticide is absorbed into skin after contact. An important question is whether the amount in the skin continues to increase with the length of the contact, or whether it increases for only a short time before leveling off. To investigate this, measured amounts of a certain pesticide were applied to 20 samples of rat skin. Four skins were analyzed at each of the time intervals 1, 2, 4, 10, and 24 hours. The amounts of the chemical (in micrograms) that were in the skin are given in the following table. a. Construct an ANOVA table. b. Can you conclude that the mean sugar concentration differs among the three days? Use the a = 0.05 level of significance.

Explanation / Answer

One-way ANOVA: amount versus duration

Method

Null hypothesis           The mean sugar concentration same among the three days
Alternative hypothesis The mean sugar concentration differs among the three days
Significance level      = 0.05
Factor Information

Factor         Levels Values
duration1       5       1, 2, 4, 10, 24

Analysis of Variance

Source    DF Adj SS    Adj MS     F-Value   P-Value
duration1    4    1.3280    0.33200     8.59   0.001
Error        15 0.5800    0.03867
Total        19   1.9080

Model Summary

       S   R-sq R-sq(adj)    R-sq(pred)
0.196638 69.60%     61.50%      45.96%

here P-value is 0.001< alpha = 0.05

so we reject H0.

i.e. we conclude that the mean sugar concentration differs among the three days.

Related Questions

Navigate

• Browse (All)
• Browse O
• Subjects

---

---

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