Using the Scientific Method…
Big Bang Theory
Forming an “alternative” hypothesis:
The alternative hypothesis, denoted by H1 or Ha, is the hypothesis
that sample observations are influenced by some non-random
cause. Although you could state a scientific hypothesis in
various ways, most hypothesis are "If, then" statements”.
Example of “If, then”:
H1: If you get at least 6 hours of sleep, you will do better on tests than if
you get less sleep.
Example of a non “if, then” hypothesis:
H1: Tomato plants exhibit a higher rate of growth when planted in compost
rather than in soil.
Using the Scientific Method…
Forming a Null Hypothesis:
The null hypothesis, denoted by H0, is usually the
hypothesis that sample observations result purely from
chance.
Null Hypothesis Examples:
H0: Tomato plants do not exhibit a higher rate of
growth when planted in compost rather than soil.
H0: Hyperactivity is unrelated to eating sugar.
Wha?
If the null hypothesis is not rejected, then we must be
careful to say what this means. The thinking on this is
similar to a legal verdict. Just because a person has
been declared "not guilty", it does not mean that he is
innocent. In the same way, just because a null
hypothesis is not rejected does not mean that the
statement is true.
The alternative hypothesis is what we are attempting
to demonstrate in an indirect way by the use of our
hypothesis test. If the null hypothesis is rejected, then
we accept the alternative hypothesis. If the null
hypothesis is not rejected, then we do not accept the
alternative hypothesis.
The Control
one
• A researcher must only measure
variable at a time, and
using a scientific control group gives reliable baseline data to
compare their results with.
• For example, a medical study will use two groups, giving one
set of patients the real medicine and the other a placebo, in
order to rule out the placebo effect. In this particular type of
research, the experiment is double blind.
• Neither the doctors nor the patients are aware of which pill they
are receiving, curbing potential research bias.
Scientific Method…
Monty Python
• Decide which organism you will test.
– Earthworm, dubia (roach), or cricket
• Decide which variable you will test:
– Light or temperature
• Decide how you will test, and write the
directions. Do NOT use “I, we, you, them…”.
Directions must be sequential and easy to
follow. (tomorrow you can modify your directions if you need to)
BRING Supplies!
If I don’t have a tool/equipment out that you might
need tomorrow….heat pad, flashlight, etc…
Please bring them in tomorrow!
I will have ice tomorrow, but you need to figure
out how you will get it around the tube.
Lets have fun!