Modified from Am J Physiol Renal
Physiol 256:F776-F779, 1989. Experiments were performed
to assess the effects of renal venous pressure on sodium excretion
in kidneys of male Wistar Rats. Kidneys were removed,
renal arteries and veins were cannulated, and kidneys perfused in
vitro. Urine was collected and analyzed for Na+, and
Fractional Na+ excretion determined at several venous pressures as
shown below. Five (5) kidneys from 5 different rats
were studied. Is there a significant linear relationship
between venous pressure and fractional sodium excretion, and is
there evidence for lack-of-fit in this relationship?
Rat
Venous Pressure (mm Hg)
Fractional Na+ excretion
1
0
1.786311
2
0
1.524096
3
0
1.458782
4
0
1.241864
5
0
1.400019
1
6.25
2.70489
2
6.25
2.446311
3
6.25
2.222388
4
6.25
2.640194
5
6.25
2.37577
1
12.5
3.633922
2
12.5
3.469036
3
12.5
3.503221
4
12.5
3.311488
5
12.5
3.189047
1
18.75
4.995299
2
18.75
4.757073
3
18.75
4.460179
4
18.75
4.698193
5
18.75
4.709743
1
25
5.675704
2
25
5.569116
3
25
5.633269
4
25
5.665157
5
25
5.282047
The format of the problem sets will be as follows (see Examples
in Sample Problem Set Excel Workbooks for details on how to present
calculations):
Define the problem and state the test or procedure that will be
used.
State null and alternative hypotheses (if hypotheses will be
tested).
State any statistical assumptions made in performing the
analysis. Where possible, assumptions should be verified using
approaches outlined in the modules.
State the probability level.
Data workup - include website URL if an online calculator is
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Calculate test statistic(s).
Compare the calculated test statistic or the calculated p-value
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Accept or reject the null hypothesis (if a hypothesis is
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problem. This should include answering any questions posed in the
problem.