BISC104
02.17.14 – 02.19.14 (Chapter 1)

Hypothesis or Theory?

What is the difference? Is there a difference? -hypothesis : possible explanation for something (narrow or specific)
-theory : based on a collection of hypothesis (broader, well supported, generally believed to be true)

How Science is Done

Barry Marshall and Robin Warren studied the stomach -they made observations -their question was WHAT CAUES ULCERS? -the Tums and Antacids didn’t help the ulcers -the hypothesis was that : the bacteria in the stomach causes ulcers -but how do you treat a bacterial infection….antibiotics -how are you going to test this? -you can’t really test this experiment on people -others began to falsify his hypothesis
-because of other scientists, helicobacter pylori was believed to cause more than 90% of duodenal ulcers and up to 80% of gastric ulcers + be treatable by antibiotics
-the germ theory supported this hypothesis by stating that germs can cause infections

Developing a Hypothesis

-Observe…Question…Possible explanation
-Testing : -general…specific -predictions are necessary (if…then)

The Process of Science

Observation  Question  Hypothesis  Predication  Test
-sometimes your results are NOT going to support your hypothesis (falsifying) -so then you go right back and create another hypothesis
-if you get information that supports your hypothesis, then you need to create alternative hypothesis and test those -you’ll get more support if you can falsify other hypothesis
-your tests will either SUPPORT or FALSIFY your hypothesis -do not say PROVE because we can always keep on learning

Hypothesis Testing

-discovery science -collecting data & making observation
-experimentation
-data -variables -independent : the variable that YOU are changing
-dependent : the variable that is the result of your change -control -the group that is NOT influenced -we are not going to change the control group -they are used for your comparative studies
-when you set up controls you have to be careful that no other factors influence your experiment (make them the same in every way BESIDES the factors that you are changing)

Designing a Controlled Experiment

-variables
-control
-subject pool -assigning people to different groups using random assignment -once you have your two groups, one group will take the placebo -placebo : a replacement (fake) for the actual experiment item
-avoid bias -blind experiment : subjects do not know -double blind : subjects + researchers do not know
-we do these blind/double blind experiments to avoid any behavior that would influence any type of results
-these types of experiments have an unbiased reporting
-when humans are not an option (animals come with pluses and minuses)
-examine the correlation between variables

Example : Stress & the common cold
-Using correlation to test hypotheses: -question : does stress affect colds
-hypothesis : an increased amount of stress makes us more susceptible to colds -test :
-results : stress MIGHT make you more susceptible to colds (correlation