Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide 18- 1

Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Elementary Statistics An Introduction to Statistics

Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide What is Statistics and How or Why is it Important?

Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide What is Statistics? 2 general meanings (1 of 2): Statistics is a field or discipline that involves using numbers (or data) to describe phenomena and/or to make decisions about those phenomena. Example: We may be interested in the level of academic achievement of KSU students. Therefore, we might use Statistics to describe KSU academic achievement through the analysis of SAT scores.

Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide What is Statistics? 2 general meanings (2 of 2): Statistics are actual numerical calculations that describe or estimate certain characteristics of a large group of people, things, places, times, etc. Example: We may be interested in whether or not KSU professors are overworked. We may then calculate the mean (or average) number of hours worked per week. This number, the mean hours worker, is an example of a statistic.

Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide How or Why are Statistics Important? Here are some examples of how Statistics is used in the modern world in a number of fields (Medicine, Business, Government, Environmental Issues, Psychology, Sociology, Education, etc.).

Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide Example 1: Medicine Physicians are interested in testing in a new drug therapy for treating Heart Disease. They take a group of 60 Heart Disease patients and randomly assign half to a group that will receive the new drug and the other half to a group that will receive a traditional treatment. After a prescribed amount of time, they compare the average cardiac fitness of both groups and make a decision concerning whether or not the new drug is more effective than the traditional one.

Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide Example 2: Business A record company is currently selling CD’s at the price of $ However, due to inflation, they need to increase the price, but do not want to raise the price so much that customers will stop buying CD’s. Therefore, they interview 2,000 customers who buy CD’s at the current price and ask whether or not they would continue to buy CD’s at the price of $ After analyzing the results of the interviews, the company estimates the porportion of customers who will continue to buy CD’s at the new price.

Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide Example 3: Government The 2008 Presidential Election is approaching rapidly. There is great interest across the nation concerning who the candidates will be. Therefore, journalists often interview potential voters and ask them for whom they will vote. Often times, these results will be summarized and reported through TV as the percentage of voters voting for ‘Candidate A’ with a certain margin of error. For Example: Our polls indicate that 55% +/- 3% of voters will be voting Democratic during this election.

Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide Example 4: Environmental Issues Scientists want to know whether or not cars running on regular gasoline emit more or less carbon dioxide than those running on premium. They take 50 cars randomly selected from all makes & models. They then run them on regular gasoline for 1 week and measure emissions. Next, they repeat this process with premium gasoline. Finally, they compare the average carbon dioxide emissions for each type of gasoline and make a decision concerning the level of air pollution based on gasoline type.

Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide Example 5: Psychology Psychologists are interested in comparing the levels of anxiety in persons suffering from clinical depression to those with a typical level of affect. Therefore, they take a group of 100 persons with depression and another group of 100 persons without depression. Next, they have each person rate their level of anxiety in different ‘everyday’ situations. Finally, they compare the average ratings from both groups, make a decision concerning the relationship between level of anxiety and depression, and report the results on a TV special

Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide Example 6: Education Reading specialists have developed a new program for teaching reading to grade school students. Before they can use the new program, they must ‘prove’ to the community of reading educators that the program really does work AND that it works better than the current program. Therefore, they take a sample of 500 students and give them the new reading instruction. Furthermore, a sample of 500 students who are matched along the lines of age, gender, ethnicity, and IQ are given the traditional reading instruction.

Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide Example 6: Education (Continued) After a 3 year trial period, both groups are administered a reading test and the average scores for both groups are compared. Finally, the researchers make a decision concerning the worthiness of the new program.

Copyright © 2006 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Slide Final Thoughts These have been just a few of the many, many ways in which Statistics are used in the modern world. A basic understanding of Statistics is necessary for objective and/or scientific investigation in ALL fields of study AND ALL professions. A thorough understanding of Statistics is ESSENTIAL for any student considering graduate school or an advanced degree.