Mouse sampling worksheet

Date
Name
Period
Perry
Sampling Methods to Study Populations
How can .0 estimate the size of a population of organisms from a sample?
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1. You estimated the number
of mice in this grid. Before you
actually count them, how many
did you estimate?
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3. Estimate the total number of
mice by multiplying the number
of mice in the top left square by
the number of total squares?
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2. Now count ONLY the
number in the top left square.
How many did you actually
count?
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4. Repeat steps 2 & 3 above
for the bottom left square:
Count = - t,
Total population from this sample = 1
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5. Repeat steps 2 & 3 above for the bottom square, 2nd from the left:
Count = V.:,
Total population from this sample = ;
6. Find the average of your samples by adding your total population from 3, 4 and 5 above and ÷ 3
Average population size =
7. Now count the entire population?
8. Compare the actual number of mice to each of your samples and the average of the samples:
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The estimation activity above is an exercise in random sampling. This is a useful tool to study populations when you
cannot count the ENTIRE population. You can obtain estimates about a population size by using the random sampling
and averaging method!
9. What is a census study?
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10. Could a census study be used in the mouse example above?
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Explain why or why not:
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11. Define the following:
a. Random sampling:
b. Bias in sampling:
c. Sampling error: (provide a specific example)
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12. List four factors that can affect a population's size:
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Created by T Harbin
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This grid represents a meadow measuring 10 m on each side.
Each grid segment is 1m X 1m. Each black dot represents one
sunflower plant.
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15. If you were to walk this meadow in the following segments,
how many sunflowers would you estimate would be in the
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G8 =
100
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Average the 3 samples above?
17. Count the entire sunflower population?
18. Compare the actual number of sunflowers to each sample and the average of those samples:
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19. Why do biologists use sampling methods?
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20. Population Sampling is usually more effective when the population has an even dispersion pattern. Clumped
dispersion patterns are the least effective. Explain why this would be the case.
21. Describe how you would use Sampling to determine the population of dandelions in your yard.
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22. In a forest that measures 5 miles by 5 miles, a sample was tak _ n to count the number of silver maple trees in the
forest. The number of trees counted in the grid is shown below. I he grids where the survey was
taken were chosen randomly. Determine how many silver maple trees are in this forest using the
random sampling technique. Show your work!
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14. Why are F1 & 66(not good choices for the question above?
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13. If you were going to estimate how many sunflowers were in
this meadow, which grid would be the best to sample?
Provide the letter and number
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