Item EM001006: Ear length varies within a population of rabbits. (Recognize a statement that describes the variability shown in a bar graph.)
The graph below shows the ear lengths of a population of rabbits.
Which of the following claims about the population do the data in this graph support?
- Ear length is changing over time in the population.
- Ear length is undergoing natural selection in the population.
- Ear length is the same throughout the population.
- Ear length varies among individuals in the population.
Pre-Test
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 572 |
6–8 n = 18 |
9–12 n = 502 |
Male n = 245 |
Female n = 283 |
English n = 511 |
Other n = 18 |
||
| A. | Ear length is changing over time in the population. | 23% | 17% | 22% | 21% | 23% | 22% | 33% |
| B. | Ear length is undergoing natural selection in the population. | 16% | 6% | 17% | 16% | 17% | 17% | 11% |
| C. | Ear length is the same throughout the population. | 3% | 0% | 4% | 4% | 3% | 4% | 0% |
| D. | Ear length varies among individuals in the population. | 57% | 78% | 57% | 59% | 57% | 57% | 56% |
Post-Test (Control)
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 274 |
6–8 n = 14 |
9–12 n = 230 |
Male n = 119 |
Female n = 130 |
English n = 237 |
Other n = 9 |
||
| A. | Ear length is changing over time in the population. | 18% | 29% | 15% | 17% | 18% | 15% | 44% |
| B. | Ear length is undergoing natural selection in the population. | 28% | 29% | 28% | 29% | 28% | 29% | 22% |
| C. | Ear length is the same throughout the population. | 2% | 0% | 3% | 3% | 2% | 3% | 0% |
| D. | Ear length varies among individuals in the population. | 52% | 43% | 54% | 50% | 53% | 54% | 33% |
Post-Test (Treatment)
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 278 |
6–8 n = 4 |
9–12 n = 248 |
Male n = 130 |
Female n = 131 |
English n = 251 |
Other n = 5 |
||
| A. | Ear length is changing over time in the population. | 13% | 25% | 14% | 12% | 15% | 13% | 20% |
| B. | Ear length is undergoing natural selection in the population. | 19% | 0% | 18% | 17% | 19% | 19% | 20% |
| C. | Ear length is the same throughout the population. | 1% | 0% | 1% | 2% | 0% | 1% | 0% |
| D. | Ear length varies among individuals in the population. | 67% | 75% | 67% | 68% | 66% | 67% | 60% |