Machine-translated by Google. Questions are authored in English.
Top

Discussion

Under a \(2^{3}\) factorial design with factors A, B, C arranged in a single replicate of two blocks, the containts of block-I (in Yate's notation) are {1, a, ab, b}. Which of the following effects is confounded with blocks ?

  • A.AB
  • B.AC
  • C.ABC
  • D.C

Answer: D

The effect confounded with blocks is C.

Block I contains 1, a, b, ab, exactly the treatment combinations in which factor C is at its low level, and block II therefore contains c, ac, bc, abc. The main effect of C is the contrast (c + ac + bc + abc) - (1 + a + b + ab), which is the same as the block difference, so C cannot be separated from blocks.

For AB the block would have to be {1, ab, c, abc}, for AC {1, ac, b, abc}, and for ABC {1, ab, ac, bc}. Confounding a main effect is unusual in practice, but it is what this allocation does.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.