Listed in the accompanying dat
Listed in the accompanying data table are birth weights (g)from a sample of 26 births. When applying the Wilcoxon rank-sumtest, what is the sum of the ranks for the sample of birth weightsof girls? Girl 3700 1000 2200 4300 3100 1900 2700 3400 2900 25004000 3400 2700 3200 Boy 3600 2700 3700 4200 3600 1800 3400 38002700 3300 3400 300
The sum of the ranks for the sample of birth weights of girlsis? .
Answer:
The answer is 174.5
Let girls be Sample 1 and boys be Sample 2.
First, we put both samples together and organize it in ascendingorder, which is shown in the table below:
Sample | Value |
2 | 300 |
1 | 1000 |
2 | 1800 |
1 | 1900 |
1 | 2200 |
1 | 2500 |
1 | 2700 |
1 | 2700 |
2 | 2700 |
2 | 2700 |
1 | 2900 |
1 | 3100 |
1 | 3200 |
2 | 3300 |
1 | 3400 |
1 | 3400 |
2 | 3400 |
2 | 3400 |
2 | 3600 |
2 | 3600 |
1 | 3700 |
2 | 3700 |
2 | 3800 |
1 | 4000 |
2 | 4200 |
1 | 4300 |
Now, that the values that are in ascending order are assignedranks to them, taking care of assigning the average rank to valueswith rank ties
Sample | Value | Rank | Rank (Adjusted for ties) |
2 | 300 | 1 | 1 |
1 | 1000 | 2 | 2 |
2 | 1800 | 3 | 3 |
1 | 1900 | 4 | 4 |
1 | 2200 | 5 | 5 |
1 | 2500 | 6 | 6 |
1 | 2700 | 7 | 8.5 |
1 | 2700 | 8 | 8.5 |
2 | 2700 | 9 | 8.5 |
2 | 2700 | 10 | 8.5 |
1 | 2900 | 11 | 11 |
1 | 3100 | 12 | 12 |
1 | 3200 | 13 | 13 |
2 | 3300 | 14 | 14 |
1 | 3400 | 15 | 16.5 |
1 | 3400 | 16 | 16.5 |
2 | 3400 | 17 | 16.5 |
2 | 3400 | 18 | 16.5 |
2 | 3600 | 19 | 19.5 |
2 | 3600 | 20 | 19.5 |
1 | 3700 | 21 | 21.5 |
2 | 3700 | 22 | 21.5 |
2 | 3800 | 23 | 23 |
1 | 4000 | 24 | 24 |
2 | 4200 | 25 | 25 |
1 | 4300 | 26 | 26 |
The sum of ranks for sample 1 i.e. girls is:
and the sum of ranks of sample 2 is: