Part 2: Random Sampling

Random Sampling Data			Actual Data
Grid Segment (number and letter)	Number of Sunflowers		Total number of Sunflowers 228 (count by hand) Average number of Sunflowers (divide total by 10) Per grid 2.28
E3	3
J10	1
G5	3
H2	3
C7	3
F4	3
D8	2
A6	3
B9	3
I1	3
Total Number of Sunflowers	27
Average (divide total by 100)	2.7
Total number of plants in meadow (multiply average by 100)	270

Analysis

1.      Compare the total number you got for sunflowers from the SAMPLING to the ACTUAL count.  How close are they? 

My numbers were 42 off from the actual count. It’s not bad but it’s kind of a 50/50 shot.

2.      Why was the paper-slip method used to select the grid segments?

The paper slip method was used to demonstrate what it would be like to pick randomly. It shows that if you pick randomly the average will be about the same.

3.      A lazy ecologist collects data from the same field, but he stops just on the side of the road and just counts the ten segments near the road. These ten segments are located at J, 1-10. When she submits her report, how many sunflowers will she estimate are in the field?

The lazy ecologist would count seven sunflowers in J, 1-10 so she would estimate that there are 70 sunflowers in the field when she submits her report.

4.      Suggest a reason why her estimation differs from your estimation.

The reason her estimations differ because she didn't pick hers randomly, she just wanted to get hers done and didn't seem to care.  

5.      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.

When a population is clumped you can’t use this method to get an accurate number. You would get a high amount of numbers in one area with a low number in the others. You couldn't use this because numbers would be everywhere and it wouldn't be accurate. As opposed to a even dispersal you can take those numbers and it would turn out to be pretty close to the actual number.

6.      Describe how you would use sampling to determine the population of dandelions in your yard.

I would use sampling to determine the population of dandelions in my yard by doing what we did in this exercise, I would section off the yard in a grid pattern. With 100 squared off sections, then count the number of flowers and then determine an average of flowers per square by dividing that number by 10. Use that averages multiply it by 100 to get the total.

7.      In an area that measures five miles by five miles, a sample was taken to count the number of desert willow trees. The number of trees counted in the grid is shown below. The grids where the survey was taken were chosen randomly. Determine how desert willow trees are in this forest using the random sampling technique. Show your calculations.

The area is 5x5 which is 25 squared, you take the five numbers given 11+7+9+5+3 which equals 35. Now taking that number 35 divide it by 5 which gives you 7. Then you will take 7 and multiply it by 25 which equals 175. That gives you 175 willow trees in that forest.