Writing a Hypothesis Unit 4

The Scientific Method The 7 basic steps of the scientific method: 1.Asking a question 2.Preliminary research 3.Making a hypothesis 4.Planning an investigation 5.Recording and analyzing data 6.Explaining the data 7.Communicating the results

The Hypothesis Constructed after preliminary background research, but before the experiment. Tentative explanation of an observation. Predicts a possible connection between the independent and dependent variable. Must be testable.

Writing the Hypothesis Written as an if/then statement. If (IV) is related to (DV), then (predict the effect). If the (IV) (describe the change), then the (DV) will (predict the effect) Ex. If the dissolved oxygen in a pond decreases, then the number of minnows will decrease. Or.. A decrease dissolved oxygen level will result in a decrease in minnow number.

Writing the Hypothesis Must include 3 elements: Independent variable Dependent variable Prediction of effect the IV will have on the DV *predictions include phrases, such as: increased/decreased, higher/lower, more/less, or faster/slower. ex. If cold temperatures reduces phytoplankton growth, then fewer phytoplankton will be present in ponds in winter.

The Alternative Hypothesis (H a ) Represents what we would like to be true Shows a positive correlation between the IV and DV Goal is to “Accept” the H a ex. Schools in which student-teacher relations are open/friendly will have less chaos than comparable schools where student-teacher relations are closed/tense

The Null Hypothesis (H o ) Indicates that NO effect will be seen between IV and DV Goal of experimentation is to “reject” the H o ex. H a : Schools in which student-teacher relations are open/friendly will have less chaos than comparable schools where student-teacher relations are closed/tense. H o : There is no difference between student-teacher relations in chaotic schools and student-teacher relations in comparable schools which experience no chaos.