Null hypothesis for an ANCOVA

1. Null-hypothesis for a One-Way
Analysis of Covariance (ANCOVA)
Conceptual Explanation

2. With hypothesis testing we are setting up a null-hypothesis
– the probability that there is no effect or
relationship – and then we collect evidence that leads
us to either accept or reject that null hypothesis.

3. As you may recall, a One-Way ANCOVA attempts to
compare the influence of one independent variable
with at least two levels (e.g., 1. Player – Football1, B-Ball2,
Soccer3,) on a dependent variable (e.g., pizza
slices consumed in one sitting) . . .

4. As you may recall, a One-Way ANCOVA attempts to
compare the influence of one independent variable
with at least two levels (e.g., 1. Player – Football1, B-Ball2,
Soccer3,) on a dependent variable (e.g., pizza
slices consumed in one sitting) . . .
. . . eliminating the effect of another independent
variable (a covariate in this case) with at least two
levels (e.g., gender)

5. Here is a template for writing a null-hypothesis for a
One-Way ANCOVA:

6. Here is a template for writing a null-hypothesis for a
One-Way ANCOVA:
There is no significant effect of [insert independent
variable] on [insert dependent variable] controlling
for [insert covariate].

7. Example #1

8. A pizza café owner wants to know which high school
athletes eat more pizza during their lunch break so she
knows which group to advertise more to. Is it football,
basketball, or soccer players? She further would like
find out if there is still effect after controlling for age.

9. A pizza café owner wants to know which high school
athletes eat more pizza during their lunch break so she
knows which group to advertise more to. Is it football,
basketball, or soccer players? She further would like
find out if there is still effect after controlling for age.
Template:
There is no significant effect of [insert independent
variable] on [insert dependent variable] controlling
for [insert covariate].

10. A pizza café owner wants to know which high school
athletes eat more pizza during their lunch break so she
knows which group to advertise more to. Is it football,
basketball, or soccer players? She further would like
find out if there is still effect after controlling for age.
Template:
There is no significant effect of [insert independent
variable] on [insert dependent variable] controlling
for [insert covariate].
Null-hypothesis:
There is no significant effect of athlete type on number
of pizza slices consumed in one sitting controlling for
age.

11. Example #2

12. A pastor of a congregation wants to know the degree to
which his parishioners report applying his messages to
their lives. He administers a survey. He decides he
would like to see what the results would be if he were
to take length of church attendance out of the
equation.

13. A pastor of a congregation wants to know the degree to
which his parishioners report applying his messages to
their lives. He administers a survey. He decides he
would like to see what the results would be if he were
to take length of church attendance out of the
equation.
Template:
There is no significant effect of [insert independent
variable] on [insert dependent variable] controlling
for [insert covariate].

14. A pastor of a congregation wants to know the degree to
which his parishioners reporting applying his messages
to their lives. He administers a survey. He decides he
would like to see what the results would be if he were
to take length of church attendance out of the
equation.
Template:
There is no significant effect of [insert independent
variable] on [insert dependent variable] controlling
for [insert covariate].
Null-hypothesis:
There is no significant effect of the new teaching
technique on parishioners reporting an internalization
of the message controlling for sermon fatigue.