Lab 2 Scientific Method Flashcards
What is a hypothesis, and what are the two hypotheses associated with each other?
A hypothesis is a testable explanation for an observed phenomenon. The two hypotheses are the null hypothesis and the Alternative Hypothesis
A Null Hypothesis is a statement that the study subjects have no preference for the (environmental) conditions of the variable you are testing.
An Alternative Hypothesis is a statement that suggests that the subjects do have a preference for one environmental condition over another;
DOES NOT INDICATE WHICH OF THESE TWO CONDITIONS THEY PREFER, DO NOT ADD BIAS OR ELSE INVALIDATE THE HYPOTHESIS. DON’T ADD TOWARDS
What and why are control variables important?
Control tests eliminate/reduce the possibility that variables other than the one you are testing are causing the observed results. Control everything so that only the testing variable causes change.
Also used as a basis for comparing for comparing the results of your experimental tests.
Why are replication/same size important?
Replication demonstrates that your results are reproducible and increases your confidence in your results. Replicating also decreases the likelihood that the observed results are due solely to chances and increases the likelihood that the results are observed from the changed variable.
What is the Chi-square (x^2) test?
Statistical test to determine the statistical significance of the test results.
The formula is Σ(Observed-Expected)^2 / Expected
What is the formula for degrees of freedom
df = n-1, N meaning the number of environmental conditions
What is the p-value
Is the value of probability that your observed results are due to random fluctuations instead of the testing variable.
What happens Chi-square (x^2) test is higher than the critical value
When the Chi-square (x^2) test is higher than the critical value. The probability of seeing your observed results in your experiment if the null was true is less than 0.05 (5%). This is highly unlikely, therefore you reject the null hypothesis and support your alternative hypothesis.
What happens Chi-square (x^2) test is the same as the critical value
When the Chi-square (x^2) test is the same as the critical value. The probability of seeing your observed results in your experiment if the null was true is equal to 0.05 (5%). Therefore you reject the null hypothesis
What happens Chi-square (x^2) test is less than the critical value
When the Chi-square (x^2) test is less than the critical value. The probability of seeing your observed results in your experiment if the null was true is higher than 0.05 (5%). Therefore you fail to reject the null hypothesis, which means your alternative hypothesis is incorrect.
