Aim: What types of data and studies exist? HW#1: Complete last slide on loose leaf

New Term Grading: Exams/Quizzes/Articles/SPSS 85% Final Exam 15% (MP3) Class participation 5% Assignments given at the end of lessons must be submitted THAT DAY and will be part of class participation grade Homework 10% Late homework WILL NOT be accepted

Exploratory Data Analysis Chapter 1 and 2 we learned about data analysis Exploratory Data Analysis: we rely heavily on plotting the data We look for patterns that suggest interesting conclusions or questions for further study However, exploratory analysis alone can rarely provide convincing evidence for its conclusions, because striking patterns we find in data can arise from many sources

What is anecdotal data? Anecdotal evidence is based on haphazardly selected individual cases, which often come to our attention because they are striking in some way. Anecdotal data are stories; this is when people use their intuition or personal experiences as data.

How reliable is anecdotal data? Does not provide proof but may assist research efforts These cases need not be representative of any larger group of cases. Can provide quantitative data Can get anecdotal evidence from personal interviews, public hearings, and surveys.

Available data Available data are data that were produced in the past for some other purpose but that may help answer a present question Example: At the Web site of the National Center for Education Statistics, nces.ed.gov/nationsreportcard/mathematics, you will find full details about the math skills of schoolchildren in the latest National Assessment of Educational Progress. Mathematics scores have slowly but steadily increased since 1990. All racial/ethnic groups, both men and women, and students in most states are getting better in math.

What is an Experimental Study? In experiments, researchers give treatments and observe to see if they cause changes in behavior. A classic simple experiment is one in which a researcher forms two groups at random and gives each group a different treatment *Random Assignment will be spoken about in the next few class sessions*

Example of Experimental Study Fifty students were divided into groups at random. One group received math instruction via a correspondence course on the Internet. The other group was given instruction on the same math skills using a traditional textbook. The purpose was to see if instruction via the Internet was more effective than traditional textbook instruction.

Characteristics of an Experimental Study Experimental Group: the group of participants receiving the treatment From Example: the group receiving the new type of instruction via the internet Control Group: the group not receiving treatment From the Example: the group receiving the instruction with a textbook

What is a Nonexperimental Study? In a nonexperimental study, researchers do not give treatments; rather they observe participants in order to describe them as they naturally exist without experimental treatment Researchers are using ways to observe participants in order to determine their attitudes, beliefs, and behaviors as they exist without experimental intervention Come in many forms Example: surveys, interviews and questionnaires

Purpose of Experiments? The purpose of an experiment is to explore cause-and-effect relationships (i.e. treatments are given to see how they affect the participants) ALTHOUGH nonexperimental studies can also be used for this purpose sometimes!

Class Work: Find some available data Visit the Internet and find two different examples of available data that is interesting to you. Explain how the data were collected and what questions the study was designed to answer. Suppose you read that an outbreak of intestinal disorders occurred in a town and the source was traced to contaminated chicken served in a popular restaurant. Is it likely the study that identified the source was “experimental’ or ‘nonexperimental?” Why? Suppose you want to now whether having parents read to preschool children has a positive effect on the children’s subsequent reading achievement. Do you think it would be better to conduct an experimental study or nonexerpimental study? Why?

Homework Are there treatments in nonexperimental studies? In an experiment, Group A was given verbal praise for being on time for appointments while Group B was given no special treatment. Which group is the control group? What is the purpose of a nonexperimental study? Is it necessary to have at least two groups of participants in order to conduct an experiment? Is a survey an experiment? Does knowing that a multiple choice test was used in a study help a consumer of research determine whether the study was experimental or nonexperimental? What is the purpose of an experimental study? A political scientist polled voters to determine their opinions on a decision by the Supreme Court. Is this an “experimental study” or “nonexperimental study?” A teacher compared the effectiveness of three methods of teaching handwriting by using different methods with different students. Did the teacher conduct an “experimental study” or “nonexperimental study?”