In order to see which variety of apple tree produces more fruit, ...

[future617RT]

In order to see which variety of apple tree produces more fruit, a farmer sets up an experiment. He has three plots of land with different soil and natural water availability. Each plot has room for eight trees.
 
  The farmer randomly selects four locations in each plot for the first variety of tree and the other four get the second variety. This experiment is
  A) completely randomized with one factor: the variety of tree
  B) randomized block, blocked by plot of land
  C) completely randomized with two factors
  D) randomized block, blocked by variety of tree
  E) completely randomized with one factor: the plot of land

Question 2

It was discovered that a larger proportion of children who slept with nightlights later developed nearsightedness, compared to children who did not sleep with nightlights.
 
  The headlines read, Leaving a light on for you children causes nearsightedness Later it was pointed out that nearsighted people have more trouble seeing in the dark and are more likely to leave lights on at night for their kids. And those same nearsighted parents are likely to have nearsighted kids. This is an example of
  A) a randomized block design.
  B) a placebo.
  C) a lurking variable.
  D) bias.
  E) a control group.

[kbennett34]

Answer to Question 1

B

Answer to Question 2

C