Homework SourseBioengineers have developed a substance that stimulates the
Bio-engineers have developed a substance that stimulates the natural production of growth hormone by livestock animals so that they grow faster and bigger. To test the efficacy of the new bio-engineered substance, 40 one-day-old female chicks of the Rhode Island Red breed, obtained from a single supplier, were randomly assigned to two groups of 20 chicks each. The control group was injected with the test substance after it had been inactivated by heat, while the treatment group was injected with the active substance. After 30 days, the following chicken weights (in grams) were measured (Note: one chick in the control group died during the experiment):
The stem and leaf displays of data for control and treatment are given below:
Control Treatment
35| 3 35|9
36|5 9 36|
37|0 6 6 37|
38|0 6 9 38|0 2 7
39|0 1 4 5 39|3 4 6
40|2 6 9 40|2 4 7
41|2 8 41|1 8 8
42|0 42|0 1 7 8
43| 43|1 5
44|8
Based on the IQR in (4) above, is there an outlier for the Treatment Group?
| Yes, the outlier observation is 393 |
Solution
Here,
Q3 = median of upper half = 424
Q1 = median of lower half = 393.5
The IQR is
IQR = Q3 - Q1 = 30.5
Now, the upper and lower fences are
Q3 + 1.5IQR = 469.75
Q1 - 1.5IQR = 347.75
As all observations are within these values, then THERE ARE NO OUTLIERS. [ANSWER]
