of the Fruitfly Data
In this activity, you will be performing an ANOVA on the
fruitfly data to determine whether the longevity of males is related to their reproductive cycle. Studies have shown that
the longevity (life span) of female fruitflies
decreases with an increase in reproduction, and this leads to the question related to males.
The design of the study placed male fruitflies in the
1) males living alone,
males living with one interested female,
living with eight interested females,
males living with one uninterested female, and
living with eight uninterested females.
The hypothesis was that the males living alone and
with the uninterested females would live longer than the males living with the interested
females. Since there are more than two group means, an ANOVA is used to determine if there
is a significant difference between the group means.
Using Excel, perform an ANOVA to
determine if there is a significant difference between the five groups.
If there is a
significant difference, you will need to determine the means that are significantly
different by doing a post hoc Tukey Test.
This data exists in Excel Data format.
1. What is the p value?
With alpha equals 0.05, what does the p value tell you, specifically, about this data?
are the F-stat and
4. Is there a statistically significant difference
somewhere between the groups?
5. How do the F-stat and F-critical values give you the answer to question four?
6. If there is a statistically significant difference somewhere between the groups, use the Tukey Test to identify between which groups, include your Tukey Table in your assignment, and list those pairs of groups.
Does reproductive activity (or the number and condition of the flies with which the males were living) affect the longevity of male fruitflies?
Oh, if you are wondering how one determines
"interest" in fruitflies, here is the scoop! Newly inseminated females will not
usually mate again for at least two days. So the males in the uninterested groups were always
living with newly inseminated females!
Copyright © 1997 Central Virginia
Governor's School for Science and Technology Lynchburg, VA