**How big is my population?**

**1:**

**Counting Big Populations:**

__How do scientists estimate the size of a large population?__

Random sampling

**2:**

**Sampling on a grid:**To count the dandelions, we'll first create a grid, then use the computer's

random number generator to tell us which grid squares to count. We'll do this 10 times, because,

as you'll see, the counts in the different grid squares will vary a lot. After you count 10 squares,

you'll use the average number per square to estimate the population of the entire lawn.

**How many dandelions are there on the grid?**

98 dandelions.

3:

**Scaling it Up:**

__What does it mean that we scaled it up?__

We multiply the estimated number by the amount of squares on the grid

4:

**Keeping it Random:**

__Why is it important to__

**select segments to count?***randomly*The species need an equal chance to be selected and to keep from having experimenter's bias.

5:

**When Size Matters:**

__What is the simplest way to determine the appropriate sample size?__

The simplest way to determine the appropriate sample size, is to graph a running average.

6:

**Bare Bones Sampling:**

__What is the difference between measuring abundance versus Presence/absence?__

Abundance is when the abundance is the actual number of individuals in a given area. Presence/absence is sampled and record whether the organism was observed or not.

7:

**Collecting P/A Data:**

*Counting Moss.*. How do we estimate sample size?we estimate by randomly picking a grid square to sample.

8:

**Impervious Surface:**

__How do we estimate impervious surface? Explain.__

We estimate impervious surface, is by using the presence absence method.

9:

**Getting Fancy:**

__What are the__

*steps*for conducting a simple transect?The

*steps*for conducting a simple transect, is to first randomly select a starting point, then lay out a transect, then lay out the sample.

**Summary:**

__Explain what you learned by doing this activity__I learned that there are many ways of sampling differently with many things. This was useful since if i find how to sample one thing it is 50% right or wrong to how i am sampling.