Environmental Science Day 2 (Scientific Method & Hypothesis Testing)


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!

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