The document discusses using a completely randomized design (CRD) to analyze data from an experiment testing the effects of 4 diets (A, B, C, D) on goat weights. It notes that the CRD does not account for differences in cage heights where the goats on different diets were located. The results show Diet A goats were in lower cages and Diet D goats higher. It recommends a randomized block design may better account for location effects. A one-way ANOVA is used to analyze if diet had an effect, with the null hypothesis being no difference in means and alternative of at least one mean being different. The ANOVA table results show a significant effect of diet on weight.

1. Notice that the completely randomized design does not account for the difference in
heights of the cages. It is just as the name suggests, a completely random assignment. In
this case, we see that the rabbits with Diet A are primarily on the bottom and those with
Diet D are on the top. A completely randomized design assumes that these locations will
not produce a systematic difference in response (coagulation time). If we do believe the
location is an important part of the process, we should use a randomized block design.
For this example, will continue to use a completely randomized design.
One-Way ANOVA
CRD! !!!!!
1. Local goat were fed with 4 different diet. After 3
months the weight of the goats were taken (data
below). Carry out analysis for i) descriptive Statistics ii)
diet difference. !!
To analyze the results of the experiment, we use a one-way analysis of variance.
The measured coagulation times for each diet are given below:
Diet A Diet B Diet C Diet D
62 63 68 56
60 67 66 62
63 71 71 60
59 64 67 61
Mean 61 66.25 68 59.75
22
The null hypothesis is
H 0 A B C D :μ = μ = μ = μ (all treatment means the same)
and the alternative is
Ha : at least one mean different.
The ANOVA Table is given below:
Response: Coagulation Time
Analysis of Variance
Source DF Sum of Squares Mean Square F Ratio
Model 3 191.50000 63.8333 9.1737
Error 12 83.50000 6.9583 Prob>F
Total 15 275.00000 0.0020