A study of fox rabies in a country gave the following
information about different regions and the occurrence of rabies in
each region. A random sample of
n1 = 16
locations in region 1 gave the following information about the
number of cases of fox rabies near that location.
x1:
Region I Data
| 2 | 9 | 9 | 9 | 6 | 8 | 8 | 1 |
| 3 | 3 | 3 | 2 | 5 | 1 | 4 | 6 |
A second random sample of
n2 = 15
locations in region II gave the following information about the
number of cases of fox rabies near that location.
x2:
Region II Data
| 2 | 2 | 5 | 2 | 6 | 8 | 5 | 4 |
| 4 | 4 | 2 | 2 | 5 | 6 | 9 |
(i) Use a calculator with sample mean and sample standard
deviation keys to calculate x1 and
s1 in region I, and x2 and
s2 in region II. (Round your answers to two
decimal places.)
| x1 | = |
| s1 | = |
| x2 | = |
| s2 | = |
(ii) Does this information indicate that there is a difference
(either way) in the mean number of cases of fox rabies between the
two regions? Use a 5% level of significance. (Assume the
distribution of rabies cases in both regions is mound-shaped and
approximately normal.)
(a) What is the level of significance?
State the null and alternate hypotheses.
H0: μ1 =
μ2; H1:
μ1 <
μ2H0:
μ1 = μ2;
H1: μ1 >
μ2
H0: μ1 >
μ2; H1:
μ1 =
μ2H0:
μ1 = μ2;
H1: μ1 â‰
μ2
(b) What sampling distribution will you use? What assumptions are
you making?
The standard normal. We assume that both population
distributions are approximately normal with unknown standard
deviations. The standard normal. We assume that both population
distributions are approximately normal with known standard
deviations. The Student’s t. We
assume that both population distributions are approximately normal
with known standard deviations. The Student’s t. We assume
that both population distributions are approximately normal with
unknown standard deviations.
What is the value of the sample test statistic? (Test the
difference μ1 − μ2. Do not
use rounded values. Round your final answer to three decimal
places.)
(c) Find (or estimate) the P-value.
P-value > 0.500 0.250 < P-value <
0.500 0.100 < P-value <
0.250 0.050 < P-value < 0.100 0.010 <
P-value < 0.050 P-value < 0.010
