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Exercise 10.2

1.
Finish the example for the twin data. Recall the paired differences were:
        pair   N      H    D

          1    74    63   11
          2    43    33   10
          3    61    41   20
          4    79    67   12
          5    80    65   15
          6    73    80   -7
          7    56    43   13
          8    98    84   14
          9    84    74   10
         10    52    48    4
(a)
Obtain the value of the Wilcoxon test statistic. (Actually determine the number of negative averages (2) and subtract it for 10(11)/2.
(b)
Obtain the p-value for a two sided-test. Use class code of course, Wilcoxon for paired designs. Conclude in terms of the problem.
(c)
Obtain (from class code) the estimated effect and the associated confidence interval. Conclude in terms of the problem.
2.
From Cushney and Peebles (1905)a, J. of Phisiology: Ten patients were selected for a study. The average number of hours that they slept was deterimed. There were two parts to the study. In Part 1, they were given by a flip of the coin one of two drugs, Laevo and Dextro, and the average (over a week) number of excess hours (over their usual average) was recorded. In Part 2 (after a wash out period), they were given the other drug, and the average (over a week) number of excess hours (over their usual average) was recorded. The data are:
       Patient     Dextro   Laevo
          1          0.7      1.9  
          2         -1.6      0.8 
          3         -0.2      1.1
          4         -1.2      0.1
          5         -0.1     -0.1
          6          3.4      4.4
          7          3.7      5.5
          8          0.8      1.6
          9          0.0      4.6 
         10          2.0      3.4
(a)
Obtain the value of the Wilcoxon test statistic, (diff = D - L).
(b)
Compare it what you would expect under H0.
(c)
Obtain the p-value for a two sided-test. Use class code of course, Wilcoxon for paired designs. Conclude in terms of the problem.
(d)
Obtain (from class code) the estimated effect and the associated confidence interval. Conclude in terms of the problem.
3.
The data below are some measurements recorded by Charles Darwin in 1878. They consist of 15 pairs of heights in inches of cross-fertilized plants and self-fertilized plants, Zea mays, each pair grown in the same pot.
        POT    CROSS    SELF 
       
          1   23.500   17.375
          2   12.000   20.375
          3   21.000   20.000
          4   22.000   20.000
          5   19.125   18.375
          6   21.550   18.625
          7   22.125   18.625
          8   20.375   15.250
          9   18.250   16.500
         10   21.625   18.000
         11   23.250   16.250
         12   21.000   18.000
         13   22.125   12.750
         14   23.000   15.500
         15   12.000   18.000
(a)
Obtain the value of the Wilcoxon test statistic, (diff = C - S).
(b)
Compare it what you would expect under H0.
(c)
Obtain the p-value for a two sided-test. Use class code of course, Wilcoxon for paired designs. Conclude in terms of the problem.
(d)
Obtain (from class code) the estimated effect and the associated confidence interval. Conclude in terms of the problem.

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Next:Exercise 11.1 Up:No Title Previous:Exercise 10.1

2000-08-26