In Exercise 3.13 an experiment conducted to assess the effects of nematodes on t
ID: 3371978 • Letter: I
Question
In Exercise 3.13 an experiment conducted to assess the effects of nematodes on the growth of tomato seedlings is described. There were four treatments corresponding to 0, 1000, 5000, and 10,000 nematodes per plant. Each treatment was applied to four plants and the growth of the plants was recorded. The raw data are given in the following table: Seedling growth 10.8 91 13.5 9.2 .4 4.6 7.4 5. Nematodes 8.2 11.3 1000 5000 0,000 5.8 5.3 3.2 7.5 a. Perform a standard ANOVA on this data. Be sure to give the ANOVA table. Test whether nematode treatment affects seedling growth. What are Ho and HA ? b. Note that "nematode" is also a numerical variable, so linear regression may be appropriate. bi. Fit the appropriate linear model. What is it? ) b2. What seedling growth is predicted at 10000 nematodes ? 12000 nematodes? b3. Find and plot the residuals b4. Conduct a statistical test to verify that the nematode P coefficient is indeed non-zero b5. In light of parts b2 & b3, what problems do you see for this model? What corrective steps do you suggest ?Explanation / Answer
a.)
H0 = The average groth of tomato seedlings is same after increasing nematodes i.e. There is no affect of nematodes on growth of tomato seedlings.
HA = The growth of tomoato seedlings on an average increases after using nematodes.
We can transform data as below:
The Anova table is given below for alpha = 0.05:
Total
The f-ratio value is 12.07974. The p-value is .000616. The result is significant at p < .05.
Hence we can reject Null Hypotheses and say that on an average growth of seedlings increase with increase in use of nematodes.
Plant Group_0 Group_1000 Group_5000 Group_1000 A 10.8 11.1 5.4 5.8 B 9.1 11.1 4.6 5.3 C 13.5 8.2 7.4 3.2 D 9.2 11.3 5 7.5