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Field Plot Technique - Experimental Design in Agriculture - Past Exam Paper, Exams of Experimental Techniques

This course addresses the needs of the student preparing for a career in agricultural research or consultation and is intended to assist the scientist in the design, plot layout, analysis and interpretation of field and greenhouse experiments. This past exam includes: Field Plot Technique, Predicted Values, Assumption of Homogeneity, Barley And Vetch, Orthogonal Contrast, Fertilizer, Sum of Crossproducts, Latin Square, Potato Yield, Experimental Error

Typology: Exams

2012/2013

Uploaded on 08/20/2013

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1)
a) What does the scatter plot above indicate about the validity of the assumptions
for the ANOVA?
b) Briefly describe the steps you would take to identify an appropriate
transformation for this data set. How would you determine if you have made the
right choice?
c) How would you report results from this experiment?
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Predicted values
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Download Field Plot Technique - Experimental Design in Agriculture - Past Exam Paper and more Exams Experimental Techniques in PDF only on Docsity!

a) What does the scatter plot above indicate about the validity of the assumptions for the ANOVA?

b) Briefly describe the steps you would take to identify an appropriate transformation for this data set. How would you determine if you have made the right choice?

c) How would you report results from this experiment?

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0 20 40 60 80 100 120 140 160

Predicted values

R e s i d u a l s

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2) You wish to evaluate the effects of two green manure treatments (barley and vetch) and a control (fallow) on yield of a subsequent sugarbeet crop grown at two fertilizer levels (low and high). Your experiment consists of all possible combinations of these two treatment factors in a Randomized Complete Block Design with three replications. Write orthogonal contrast coefficients that would address the following questions:

  1. Do the green manure treatments affect sugarbeet yield?
  2. Do barley and vetch differ in their effects on sugarbeet yield?
  3. Does fertilizer affect sugarbeet yield?
  4. Is the difference between the fallow and the green manure treatments the same at both levels of fertility?
  5. Is the difference between barley and vetch the same at both levels of fertility?

Fill in the appropriate coefficients below the corresponding treatment combinations:

Fertilizer: Low, Low, Low, High, High, High, Manure: Fallow Barley Vetch Fallow Barley Vetch Means 13.5 15.2 22.0 19.3 23.9 26. Contrast # 1 2 3 4 5

a) How would you verify that these are valid contrasts?

b) Describe how you would verify that these contrasts are orthogonal to each other (give one example).

c) Is this a complete set of orthogonal contrasts? How do you know?

d) Select one of the contrasts that you have defined and calculate the Sums of Squares for the contrast using the means in the table.

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4) Potato yields were measured in an RBD experiment with four replications. The treatments K, M, and N were applied in a complete factorial, with two levels of each treatment. K = Potassium sulfate 0 vs. 100 kg/ha (K 2 0) M = manure 0 vs. 8 t/ha N = Ammonium sulfate 0 vs. 50 kg/ha (N)

Average Potato Yields t/acre

Interpret the results from this experiment. How would you summarize and report your findings? (you may right on the next page)

The GLM Procedure

Dependent Variable: yield

Sum of Source DF Squares Mean Square F Value Pr > F

Model 10 384.5825531 38.4582553 57.41 <.

Error 20 13.3968405 0.

Corrected Total 30 397.

R‐Square Coeff Var Root MSE yield Mean 0.966338 9.081070 0.818439 9.

Source DF Type III SS Mean Square F Value Pr > F

block 3 9.1378345 3.0459448 4.55 0. K 1 157.7280277 157.7280277 235.47 <. M 1 222.3475760 222.3475760 331.94 <. KM 1 15.5831169 15.5831169 23.26 0. N 1 5.8768573 5.8768573 8.77 0. KN 1 0.7588641 0.7588641 1.13 0. MN 1 0.0010078 0.0010078 0.00 0. KM*N 1 0.3023715 0.3023715 0.45 0.

Control (No K,M,N) 3. K only 8. M only 9. N only 3. K + M 12. K + N 9. M + N 10. K + M + N 13.

20 pts

Answer to question #