Section 1.4 The Reality of Conducting a Study HAWKES LEARNING SYSTEMS math courseware specialists Copyright © 2008 by Hawkes Learning Systems/Quant Systems, Inc. All rights reserved.

Subjects – people, animals, or things being studied. Participants – term used when the subjects of a study are people. Treatment – characterizes an experiment; applied to some or all subjects. Treatment Group – a group in which researchers apply a treatment. Control Group – a group identical to the treatment group except that no treatment is applied. Experiment: Introduction to Statistics 1.4 Reality of Conducting a Study HAWKES LEARNING SYSTEMS math courseware specialists

Single-Masked – when the subjects do not know in which group they have been placed. Double-Masked – when neither the subjects nor the people interacting with the subjects know to which group the subjects belong. Placebo – a substance that appears identical to the actual treatment. Experiment: Introduction to Statistics 1.4 Reality of Conducting a Study HAWKES LEARNING SYSTEMS math courseware specialists

Institutional Review Board (IRB) Informed consent Human or animal subjects Confidentiality Ethical Concerns: Bias Researcher bias Sampling errors Non-sampling errors Practical Concerns: Introduction to Statistics 1.4 Reality of Conducting a Study HAWKES LEARNING SYSTEMS math courseware specialists

Errors: Sampling Errors Non-Sampling Errors Dropout – a participant who begins the study but fails to complete it. Poor sampling frame Participation bias – when there is a problem with either the participation, or lack thereof, of those chosen for the study. Processing error – an error as simple as a typo. Lying or faulty memory Non-adheres – subjects who stray from the directions they were given. Confounding variables – factors that influence the results of the study that the researchers did not, or could not, account for. Introduction to Statistics 1.4 Reality of Conducting a Study HAWKES LEARNING SYSTEMS math courseware specialists

Consider preparing a research proposal for the following question, “what percentage of 11 to 16 year olds smoke cigarettes?” Something to Ponder: What are some possible issues of getting informed consent, confidentiality, going to the IRB, dealing with human subjects, bias? Introduction to Statistics 1.4 Reality of Conducting a Study HAWKES LEARNING SYSTEMS math courseware specialists

CompuTech is a large computer company with hundreds of thousands of customers across the country. They are interested in knowing the percentage of customers that are satisfied enough with their purchases to continue buying CompuTech products in the future. The company hires an independent research firm to conduct the study. The firm randomly selects 50 customers from each of the following metropolitan areas: New York, Los Angeles, and Chicago. They find that 77% of the customers surveyed are satisfied with their CompuTech purchase and plan to continue buying CompuTech products in the future. Using statistical methods, the firm estimates that between 74% and 80% of all CompuTech customers will continue doing business with the company. Identify the population. All CompuTech customers Identify the sample. 150 customers Identify any statistics. 77% of the customers surveyed are satisfied Introduction to Statistics 1.4 Reality of Conducting a Study HAWKES LEARNING SYSTEMS math courseware specialists

CompuTech is a large computer company with hundreds of thousands of customers across the country. They are interested in knowing the percentage of customers that are satisfied enough with their purchases to continue buying CompuTech products in the future. The company hires an independent research firm to conduct the study. The firm randomly selects 50 customers from each of the following metropolitan areas: New York, Los Angeles, and Chicago. They find that 77% of the customers surveyed are satisfied with their CompuTech purchase and plan to continue buying CompuTech products in the future. Using statistical methods, the firm estimates that between 74% and 80% of all CompuTech customers will continue doing business with the company. Identify the parameter. Between 74% and 80% of all customers are satisfied What sampling technique was used? Stratified sampling Is the study biased? If so, what type of bias occurred? Sampling errors since the population of the U.S. was not represented Introduction to Statistics 1.4 Reality of Conducting a Study HAWKES LEARNING SYSTEMS math courseware specialists

Consider the following phrase, “the firm estimates that between 74% and 80% of all CompuTech customers will continue doing business with the company.” Is this an example of descriptive or inferential statistics? Inferential Introduction to Statistics 1.4 Reality of Conducting a Study HAWKES LEARNING SYSTEMS math courseware specialists