A marine biologist claims that the mean length of mature female pink seaperch is different in fall and winter. A sample of 12 mature female pink seaperch collected in fall has a mean length of 119 millimeters and a standard deviation of 11 millimeters. A sample of 10 mature female pink seaperch collected in winter has a mean length of 114 millimeters and a standard deviation of 8 millimeters. At alphaequals0.01, can you support the marine biologist's claim? Assume the population variances are equal. Assume the samples are random and independent, and the populations are normally distributed. Complete parts (a) through (e) below.
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Part 1
(a) Identify the claim and state Upper H 0 and Upper H Subscript a.
Which is the correct claim below?
A.
"The mean length of mature female pink seaperch is greater in the fall than in the winter."
B.
"The mean length of mature female pink seaperch is greater in the winter than in the fall."
C.
"The mean length of mature female pink seaperch is different in fall and winter."
Your answer is correct.D.
"The mean length of mature female pink seaperch is the same in fall and winter."
Part 2
What are Upper H 0 and Upper H Subscript a?
The null hypothesis, Upper H 0, is
mu 1 equals mu 2 .
The alternative hypothesis, Upper H Subscript a, is
mu 1 not equals mu 2 .
Part 3
Which hypothesis is the claim?
The null hypothesis, Upper H 0
The alternative hypothesis, Upper H Subscript a
Your answer is correct.
Part 4
(b) Find the critical value(s) and identify the rejection region(s).
Enter the critical value(s) below.