IntroductionIntroduction

Wed, Aug 31, 2005Wed, Aug 31, 2005

IntroductionIntroduction

SyllabusSyllabus LecturesLectures AssignmentsAssignments Page xi – Interactive ExercisesPage xi – Interactive Exercises Page xvi – Graphing CalculatorPage xvi – Graphing Calculator

The Scientific MethodThe Scientific Method

Formulate a theory.Formulate a theory. Collect some data.Collect some data. Summarize the results.Summarize the results. Make a decision.Make a decision.

The Scientific MethodThe Scientific Method

Formulate a theory – Chapter 1.Formulate a theory – Chapter 1. Collect some data.Collect some data. Summarize the results.Summarize the results. Make a decision.Make a decision.

The Scientific MethodThe Scientific Method

Formulate a theory – Chapter 1.Formulate a theory – Chapter 1. Collect some data – Chapters 2 – 3.Collect some data – Chapters 2 – 3. Summarize the results.Summarize the results. Make a decision.Make a decision.

The Scientific MethodThe Scientific Method

Formulate a theory – Chapter 1.Formulate a theory – Chapter 1. Collect some data – Chapters 2 – 3.Collect some data – Chapters 2 – 3. Summarize the results – Chapters 4 Summarize the results – Chapters 4

– 5.– 5. Make a decision.Make a decision.

The Scientific MethodThe Scientific Method

Formulate a theory – Chapter 1.Formulate a theory – Chapter 1. Collect some data – Chapters 2 – 3.Collect some data – Chapters 2 – 3. Summarize the results – Chapters 4 Summarize the results – Chapters 4

– 5.– 5. Make a decision – Chapters 6 – 14.Make a decision – Chapters 6 – 14.

The Scientific MethodThe Scientific Method

Formulate a theory – Chapter 1.Formulate a theory – Chapter 1. Collect some data – Chapters 2 – 3.Collect some data – Chapters 2 – 3. Summarize the results – Chapters 4 – Summarize the results – Chapters 4 –

5.5. Make a decision – Chapters 6 – 14.Make a decision – Chapters 6 – 14.

Theoretical underpinnings – Chapters 6 – Theoretical underpinnings – Chapters 6 – 8.8.

Making decisions in a variety of Making decisions in a variety of situations – Chapters 9 – 14.situations – Chapters 9 – 14.

Formulate a TheoryFormulate a Theory

This example is taken from Chapter This example is taken from Chapter 14, p. 941.14, p. 941.

Based on reports from patients, Based on reports from patients, researchers formulate the theory that researchers formulate the theory that the following allergy-relief medications the following allergy-relief medications cause insomnia in some patients.cause insomnia in some patients. Claritin-DClaritin-D LoratadineLoratadine PseudoephedrinePseudoephedrine

Formulate a TheoryFormulate a Theory

This theory will be tested by posing This theory will be tested by posing it as a question with two competing it as a question with two competing answers.answers.

Question: Do these medications Question: Do these medications cause insomnia?cause insomnia?

Formulate a TheoryFormulate a Theory

The possible answers are stated The possible answers are stated more precisely as two competing more precisely as two competing hypotheses:hypotheses: ““Null:” There is no difference in the Null:” There is no difference in the

insomnia rates among users of these insomnia rates among users of these medications nor between them and non-medications nor between them and non-users.users.

““Research:” There are differences in the Research:” There are differences in the insomnia rates.insomnia rates.

Collect Some DataCollect Some Data

3036 subjects, some users and some 3036 subjects, some users and some non-users, were studied.non-users, were studied.

Treatment GroupTreatment Group

Clar.-DClar.-D Lora.Lora. Pseud.Pseud. PlacebPlaceboo

InsomnInsomnia?ia?

YesYes 164164 2222 104104 2828

NoNo 859859 521521 444444 894894

Summarize the ResultsSummarize the Results

We use some fancy formulas, or use We use some fancy formulas, or use the TI-83, and compute a special the TI-83, and compute a special quantity:quantity:

22 = 154.22. = 154.22.

Summarize the ResultsSummarize the Results

We use some fancy formulas, or use We use some fancy formulas, or use the TI-83, and compute a special the TI-83, and compute a special quantity:quantity:

22 = 154.22. = 154.22. (If there really is no difference in the (If there really is no difference in the

insomnia rates, then we “expect” insomnia rates, then we “expect” this calculation to yield the value 3, this calculation to yield the value 3, plus or minus a bit.)plus or minus a bit.)

Make a DecisionMake a Decision

We compare this to a value that we We compare this to a value that we look up in a table, or use the TI-83:look up in a table, or use the TI-83:

Critical value = 7.815.Critical value = 7.815. Since Since 22 is is largerlarger than the critical than the critical

value, we conclude that the value, we conclude that the “research” hypothesis is correct: “research” hypothesis is correct: There is a difference in the insomnia There is a difference in the insomnia rates.rates.

Some QuestionsSome Questions

Does this procedure Does this procedure proveprove that the that the medications medications causedcaused the insomnia? the insomnia?

Does it show that the insomnia rates Does it show that the insomnia rates were were higherhigher for the groups that took for the groups that took the medications?the medications?