Name:
Section:
Date:
Graded Course Assignment 4: Statistics
Complete the practice scenarios and determine if there is a significant difference between the means
using a Student’s t-test (alpha level= 0.05). Answer all questions and attach the t-test spreadsheet with
calculations associated with each scenario.
1. A researcher wishes to learn if a certain drug slows the growth of tumors. She obtains mice
with tumors and randomly divides them into two groups. She injects one group of mice with
the drug and uses the second group of mice as a control. After 2 weeks, she sacrifices the mice
and weighs the tumors. The mass of tumors for each group of mice is below.
The researcher is interested in learning if the drug reduces the growth of tumors.
Her hypothesis is: The mean weight of tumors from mice in Group A will be less than the mean
weight of tumors from mice in Group B.
Tumor mass (g) of Group A mice
Treated with Drug
0.72
0.68
0.69
0.66
0.70
0.63
0.71
0.73
0.68
0.71
Tumor mass (g) of Group B mice
Control- Not Treated
0.71
0.83
0.89
0.78
0.68
0.74
0.75
0.80
0.80
0.78
a. Is this a one-tailed or two-tailed t-test? Why?
b. Perform a t-test using the programmed Excel worksheet.
c. What is the calculated p-value?
d. Is the researcher’s hypothesis accepted or rejected? Why?
Attach the Excel t-test calculation worksheet.
Reference:
Gregory, M. (2014, August). Statistical analysis- The t-test. Retrieved August 5, 2014 from
http://biology.clc.uc.edu/courses/bio303/statanal.htm
2. A group of ecology students was studying and comparing two different forest areas by taking 20
sample plots in each area.
The researcher formulated the following hypothesis: The mean difference of sugar plus red maple trees
between Woods A and B will be different.
In each wooded area the combined number of sugar plus red maple trees in each of the 20 plots was
found to be:
Woods A
Plot Data
Woods B
Plot Data
0
6
7
0
1
3
2
9
7
3
1
9
8
2
1
5
7
5
7
3
9
6
2
7
6
8
6
5
0
2
3
2
4
7
9
8
7
1
7
8
a. Is this a one-tailed or two-tailed t-test? Why?
b. Perform a t-test using the programmed Excel worksheet.
c. What is the calculated p-value?
d. Is the researcher’s hypothesis accepted or rejected? Why?
Attach the Excel t-test calculation worksheet.
Reference:
Carter, S.J., (2005, March 29). Statistical analysis of data. Retrieved August 4, 2014 from
http://biology.clc.uc.edu/courses/bio303/statanal.htm