Matschie's Tree Kangaroo
Enrichment Interaction Study
Problem:
How does the mean interaction time with enrichment items differ between the male and the female tree kangaroo?
Subjects
(Matschie's Tree Kangaroo's at the Columbus Zoo)
Kea
(female)
Almond Joy (male)
Hypothesis:
Null Hypothesis: The male tree kangaroo's mean interaction time with enrichment items will be the same and the female tree kangaroo's mean interaction time with enrichment items.
H0: µ1-µ2 = 0
Alternative Hypothesis (claim): The male tree kangaroo's mean interaction time with enrichment items will not be the same as the female tree kangaroo's mean interaction time with enrichment items.
H1:
µ1-µ2
not equal to 0
Statistical Test:
An F test was used to determine if there was a significant difference between the males variance of interaction time with enrichment items and the females variance interaction time with enrichment items. Then a t-test of independent sample means (assuming equal variances) was used to compare the male and the female tree kangaroo's mean interaction time with enrichment items. The confidence level for the study was 95%.
Abstract:
The
tree kangaroo's were observed Monday through Thursday for two hours each.
Enrichment days were Monday's and Wednesdays and the interaction time
with enrichment items was observed in seconds.The Columbus Zoo and Aquarium
have two tree kangaroos, Almond- Joy (male) and Kea (female), which will
be the subjects observed for this study. Since tree kangaroos are solitary
animals, especially in captivity, only one tree kangaroo is on exhibit
each day.
Dr. Harder, a professor from Ohio State University, is conducting a study
on the levels of cortisol in kangaroo feces. Cortisol is a stress hormone
that is made in the adrenal glands and with levels that change throughout
the day. This study is being conducted to determine how enrichment items
affect the cortisol levels in the Matschie’s tree kangaroos.
Movies:
Results:
The purpose of this study was to determine if there was a significant difference between the male tree kangaroo's mean interaction time with enrichment items and the female tree kangaroo's mean interaction time with enrichment items.
This includes the results of the t tests of independent sample means. The data gathered for the male and the female Matschie's tree kangaroo's.
Figure 1: Bar graph of the means
This study was conducted at an alpha level of 0.05. Figure 1 shows the bar graph of the means of the male and the female tree kangaroo's interaction time with enrichment. This graph shows that there is not a significant difference between the male and the female tree kangaroo's mean. The mean of the male tree kangaroo's interaction time with enrichment was found to be 1210.23, while the female tree kangaroo's mean interaction time with enrichment was found to be 1653.82 (seconds). The results of the t test failed to reject the null therefore there is not a significant difference between the male and the female tree kangaroo's mean interaction time with enrichment items.
Summary
The results of the t test found that there is not a statistical significant
difference between the male and the female tree kangaroo's mean interaction
time with enrichment items.
Figure 2: Bar graph of the variances
This study was conducted at an alpha level of p= 0.05. Figure 2 shows that there is no significant difference between the two sample variances. The sample of the male tree kangaroo shows the variance to be 2410023.69 (seconds) and the sample of female tree kangaroo shows the variance to be 4007131.65 (seconds). The study conducted failed to reject the null therefore there is no significant difference between the male and the female tree kangaroo's variance.
Summary
The results of the f test were not found to be statistically significant
and did not provide evidence necessary to reject the null hypothesis
in favor of the alternative hypothesis, which stated that the variances
of the tree kangaroos are not equal.
Table 1: Hypthesis Results(means, variances & Confidence interval)
table 1 shows the hypothesis results including an n value, mean and variance for both the male and the female tree kangaroo's. Also in table 1, statistics and confidene intervals are present.
Summary
The results of both statistical tests (f test and t test) were both
shown in table 1. There is not a significant difference between the
male and the female tree kangaroo's variance also, there is not a significant
difference between the male and the female tree kangaroo's mean interaction
time with enrichment items. There is not enough evidence to support
the claim for both the f test and the t test conducted.
Conclusion:
An f test was conducted to determine if there was a significant difference between the male and the female's variance. The f test failed to reject the null hypothesis, which means that there is not a significant difference between the sample's variances. Then a t test assuming equal variances was conducted. The results of the t test were not able to reject the null hypothesis. The mean interaction time with enrichment was not significantly different than the females mean interaction time with enrichment.
Implications:
This study may show the keepers of the Matschie's tree kangaroo's that there is not a significant difference between the male and the female tree kangaroo's variance and the male's interaction time with enrichment items is not significantly different form the female's interaction time with enrichment. Both the male and the female tree kangaroo's enjoyed their enrichment.
Columbus Zoo & Aquarium School: 2006
© 2006 All rights reserved.