A researcher wanted to examine if soil type had any effects on the heights of daylilies. Ten bulbs of daylilies were planted in each of the three different types of soil. The thickness of the soil X) was also measured for each pot. After three months, the heights of the plants
Y) were measured. Below are the group means of the study.

-If there is a substantial negative correlation between X and Y, the error variation for ANCOVA as compared to that for ANOVA will be
A) less.
B) the same.
C) greater.
D) unpredictably different.

Question

A researcher wanted to examine if soil type had any effects on the heights of daylilies. Ten bulbs of daylilies were planted in each of the three different types of soil. The thickness of the soil  X) was also measured for each pot. After three months, the heights of the plants
 Y) were measured. Below are the group means of the study.

-If there is a substantial negative correlation between X and Y, the error variation for ANCOVA as compared to that for ANOVA will be
A) less. 
B) the same. 
C) greater. 
D) unpredictably different.

Quizplus · Accepted Answer

If the correlation is substantial, then error variance will be reduced in ANCOVA regardless of its sign.)

A Researcher Wanted to Examine If Soil Type Had Any