An experiment on sugar beets compared times and methods of applying artificial (N-P-K) fertilizer, using a completely randomized design. The four treatments were:
Treatment 1 - no artificials(control)
Treatment 2 - artificials applied in January and ploughed into soil
Treatment 3 - artificials applied in January and broadcast
Treatment 4 - artificials applied in April and broadcast.
(a) Write down a set of orthogonal contrasts for comparing:
(i) the effects of artificials vs. control
(ii) January application of artificials with April application
(iii) Ploughing with broadcasting for the January application of artificials.
(b) The treatment means (of yields, in tens of kg. per ha) were
__ __ __ __
X1. =38.7 X2. = 48.7 X3. = 48.8 X4. = 45.0
each with a standard error of 1.22 on 16 d.f. Calculate 95% confidence intervals for the contrasts above.
The solution contains the determination of orthogonal contrasts in a completely randomized design.