Hello and welcome to our second day of

our environmental science lab. Our lesson objectives for today will be to list the

points that make up the scientific method. We will discuss hypothesis

testing. And we will plot data and graph a best-fit line. Okay! Here we have the

scientific method, and it’s the same one you did in grade school except we added a few more points for college. We of course asked the question. We

formulate a hypothesis. We run experiments. And we collect accumulated scientific

data. Now before I go all the way through the scientific method, we are going to

stop here and we are going to test our hypothesis, view data in a scatter plot,

and graph a best fit line. We wanted to see if there was a correlation between a

person’s arm length and their height that was our hypothesis. So, we had five

classmates and with me that made six. And, we measure everybody’s arm length, which is the first column here highlighted. Then, we measure everyone’s height, which is the second column that’s highlighted. And, we wanted to graph this data, so the

arm length was our y-axis. And the height we graphed on the x-axis. So here is our

graph and here are the points on the graph. Now many of you may be used to

points in algebra where they may be in a linear setup, but here the data pretty

much throws your points all over. And, this is what we call a scatter plot. And,

what we do to graph these is we have a best fit line, What we try to get the

line to get as close to the data points as possible. It’s not going to be perfect.

And the way we try to find out how the data is related since it’s not in a line

is we want to find the slope of that data. And, again many of y’all may

remember from algebra we had the rise over run. We had to find a change in the

y coordinate over the change in the x coordinate. And, here is the formula right

here where we have y2 minus y1 divided by x2 minus x1. But we can’t use this

formula because these points are not on the same line. So, pretty much what we are going to do is just simply get the slope of each point. We are going to have Y and

we’re gonna divide it by X. So, we go back to our original data and of course the

arm length is y the height is X and we divide Y by X and here as you can see in

the highlighted portion is what we get for our slope and you can see most of

those slopes are pretty much close together in value. Now, here is our average slope value. Okay, now let’s go back to our graph and

here’s one of our best fit lines. Now notice how everything is close to that

line except for this point. With this being such an anomaly, as you can see here

compared to all the other ones, we may just go ahead and just remove that out

of our data. Okay! So, now we go back to our scientific

method and we at this point collected the accumulated scientific data. We can

revise the original hypothesis. Next, we make our conclusion. We didn’t do that

here. We pretty much just showed how to graph the data. We never really analyzed

it. But, the last thing to do is to publish our results for a peer review.

Your fellow students need to look at it, your professor, department heads,

professors from other institutions. They may want to share your data or you may want to look at theirs. And, that is it for this video!