Next:Exercise 9.2 Up:No Title Previous:Exercise 8.3

# Exercise 9.1

1.
To set ideas work on this simple data set.
```      X   12 15 18
Y   16 19 25 28```
(a)
Obtain all 12 differences (Y minus X).
(b)
Next obtain the point estimate, the median of the differences.
(c)
Subtract this estimate from the Y's and obtain the value of the Wilcoxon test statistic.
2.
For the last problem, use the following list of random numbers to obtain 2 resampled median of differences.
```          2    9    2    2    7    2    2    3    0    8    8    1    9    8    8
2    3    3    4    0    9    2    1    0    7    9    3    6    6    2
3    7    6    8    8    7    0    5    0    3    4    3    5    7    7
3    4    5    0    1```
3.
Consider the batting averages of the switch hitters and the left-handed hitters from the baseball data set. Using class code  Two-Sample Hypothesis and CI (Wilcoxon), obtain the estimate of the difference (Left minus switch) of batting averages and determine a 95% confidence interval for the difference. What does the interval mean in terms of the problem?
```      Switch  .212   .218   .236   .242   .251   .251   .254   .261   .270  .282
Left   .238   .271   .279   .283   .284   .290   .300   .303```
4.
Consider the following samples of Italian and Etruscan skull sizes. Use class code, Two-Sample Hypothesis and CI (Wilcoxon), to obtain the estimate of difference between a typical Etruscan skull and an Italian skull. Obtain a 95% confidence interval and interpret it in terms of the problem.
```      Ital.  134    132    126    134    131    130    130    125    132    126
Etru.  141    145    145    146    142    126    144    146    154    149    143 131```
5.
Let  be the difference in weight between a typical pitcher and hitter, professional baseball players. Using class code,Two-Sample Hypothesis and CI (Wilcoxon) , estimate  and determine a 95% confidence interval for it based on the following data. What does the interval mean in terms of the problem?
```      Hitters:
155    155    160    160    160    166    170    175    175    175    180
185    185    185    185    185    185    185    190    190    190    190
190    195    195    195    195    200    205    207    210    211    230

Pitchers:
160    175    180    185    185    185    190    190    195    195    195
200    200    200    200    205    205    210    210    218    219    220
222    225    225    232```

Next:Exercise 9.2 Up:No Title Previous:Exercise 8.3

2000-08-26