Research and Statistics

Psychology 30

Chapter Objectives

     To understand the scientific method of research. To appreciate the methods, issues and challenges in conducting research. To name the different types of psychological research and some of the hazards of these.

To organize and integrate new knowledge and understandings within the discipline of psychology. To organize and integrate new knowledge and understandings with other disciplines.

Journal Entry # 2

 My life as a statistic... For the next 10 minutes, write a journal entry based on the ways that you, the things you do, the things you enjoy, or the things you don’t enjoy are measured. For example: I am counted in the number of students that attend Ituna School. I am counted as a person in my family. I am counted as a member of the volleyball team. http://www.online-stopwatch.com/

How do they know?

 How do researchers gather information, data, statistics and specific research that when trying to create and prove their hypothesis’?

Gathering Data

 Researchers use specific methods depending on the type of research that they are trying to conduct.  For example: A psychologist who is interested in personality theories might begin with intensive case studies of individuals.

 The data that is gathered by researchers must be valid. Validity

is the process of verifying that a claim is correct, or disproving it. When something is valid, it verifies the researcher’s theory.

Samples

 Suppose a psychologist wants to know how the desire to get into college affects the attitudes of high school juniors and seniors. It would be impossible to study every junior and senior in the country. Instead, the researcher would select a sample, a relatively small group of the total population under study- in this case, all high school juniors and seniors.

Samples

 Samples must be representative of the population a researcher is studying.  If we wanted to know how tall the average grade 12 boy at Ituna School was, we would want to make sure that our sample included both short and tall boys in our school so that our sample itself would not be biased.  There are two ways of avoiding a biased sample. o Random sample: taking a sample at random, like drawing names from a hat and having those boys be part of the study o Stratified sample: deliberately choosing individuals who represent various heights in our school, some short, some “medium” and some tall young men.

Correlations and Explanations

 Correlations are used in descriptive studies when scientists or researchers want to observe and describe.

 Correlations describe the degree of relatedness between two sets of data. There are two types of correlations, positive correlations and negative correlations.

Positive Correlations

 There is a positive correlation between high IQ scores and high academic success. High IQ scores tend to go with high grades.

 There is a negative correlation between smoking cigarettes and living a long and healthy life. The more a person smokes, the fewer years he or she may live.  Can you think of 5 positive correlation statements and 5 negative correlation statements?

Experiments

 How are experiments conducted? (Handout)  Experiments enable the researcher to control the situation to decrease the possibility that unnoticed, outside factors will influence the end result. 

Experiments are meant to prove or disprove hypothesis’.

Variables

 When scientists conduct experiments they think in terms of variables. Variables are conditions and behaviors that are subject to a variation or change.  There are two types of variables. Independent variables and dependent variables. Can you guess what these two variables entail?

Independent Variables

 The independent variable is the variable experimenters manipulate so they can observe its effects. Example: Effect of drug dosage on symptom severity In a study of how different doses of a drug affect the severity of symptoms, a researcher could compare the frequency and intensity of symptoms when different doses are administered. Here the independent variable is the dose.

Dependent Variables

 Dependent variables are the variables that researchers believe will be affected by the independent variable. Example: Effect of drug dosage on symptom severity.

In a study of how different doses of a drug affect the severity of symptoms, a researcher could compare the frequency and intensity of symptoms when different doses are administered. Here the independent variable is the dose and the dependent variable is the frequency/intensity of symptoms.

Other Variable Examples

Effect of education on wealth

 In sociology, in measuring the effect of education on income or wealth, the dependent variable is level of income/wealth and the independent variable is the education level of the individual.

Effect of time on speed (measurement of acceleration)

 In measuring the acceleration of a vehicle, speed varies with time but time does not vary with speed. Here, time is the independent variable, and speed is the dependent variable

Experimental Groups

 Subjects who undergo experiments are referred to as

experimental groups.

 Because there is a chance that people will act differently in a controlled environment scientists and researchers often set up two different groups, an experimental group and a control group.  Control Groups are treated the same way as the subjects in the experimental group, except that the experimental treatment is not applied.

Control Groups are a MUST!

 Control groups are absolutely necessary in experiments because without them a scientist or researcher can’t be certain that the experimental group is actually reacting to what he or she thinks it is reacting to.

Control Group Examples

  “One example might be testing plant fertilizer by giving it to only half the plants in a garden: the plants that receive no fertilizer are the control group, because they establish the baseline level of growth that the fertilizer-treated plants will be compared against. Without a control group, the experiment cannot determine whether the fertilizer-treated plants grow more than they would have if untreated.” http://en.wikipedia.org/wiki/Scientific_control Greys Anatomy Example

Studies

    Case Studies are scientific biographies of an indivudla group. Most case studies focus in a particular disorder or experience. (We experienced this when we watched the story of Genie.” Surveys are sometimes thought of as “impersonal” but are the most practical way to gather data on the attitudes, beliefs, and experiments of large numbers of people. A survey can take the form of interviews, questionnaires or a combination of the two. Longitudal Studies cover long periods of time, making them time consuming and precarious. However, they are a great way to study consistencies and inconsistencies over a long period of time. Cross- Sectional Studies are studies that divide the experimental groups into small groups, often based on age categories.

Survey Assignment

 In groups of two or three people, you will be asked to create a survey to administer students or teachers at Ituna School.  You will need to make sure that you come up with a question or hypothesis at the beginning of your survey planning process so that you are clear about exactly what your group is looking for.  Each person in the group will be responsible for writing a one page summary of the survey process including the group’s initial hypothesis, the experimental group chosen, the survey results and a summary of your group’s hypothesis.

Avoiding Errors in Doing Research

 No matter how objective humans or scientists may try to be, there is always a chance that we will find exactly what we are trying to find, overlooking important evidence.

 Has this ever happened to you?

 This is known as the self-fulfilling prophecy.

How do we avoid the Self-fufilling Prophecy?

  We can avoid this by using what is known as the double

blind technique.

Suppose a psychologist wants to study the effects of a particular tranquilizer. She might give the drug to an experimental group and a placebo (a harmless substitute for the drug) to a control group. The next step would be to compare their performances ona serioes of tests. This is a single blinded experiment.The subjects are “blind” in the sense that they do not know whether or not they have received the tranquilizer or the placebo.

Double Blind Experiments

 Double blind experiments take place when both the researcher also doesn’t know which people in the group are actually part of the control group and who are not. This type of experiment eliminates the possibility that the researcher will unconsciously find what they expect to find regarding the use of the drug, or the hypothesis they have formulated.

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What are some of the ethical issues in research?

Confidentiality is the right of privacy for subjects concerning their participation in research. All steps must be taken to assure that subjects’ participation is confidential. If any possibility exists that someone other than the researcher may have access to the data, the subjects must be informed of this possibility before they provide their informed consent to participate (Buskist, Carlson, Enzle and Heth, 1997, p. 42).  Informed consent requires that potential subjects understand exactly what is expected of them during the course of the research and that the investigator protects participants from physical and psychological discomfort, harm, and danger (Buskist et al., 1997, p. 42).  Debriefing requires that research participants be given full information about all aspects of the study after they have participated in it, thus assuring that they leave with a full understanding of its purpose, and receive a full disclosure of the information gathered (Baron et al., 1998, p. 31).

Descriptive and Inferential Statistics

 Read the information found on pages 509-513 of your textbook. Be sure to make notes on the different kinds of statistics and be able to differentiate between the two.  Which type of stats would you argue is most useful when summarizing information? Why?

Mode, Median and Mean Review

 The mode is the most frequent score. In a graph, the mode is the peak of the graph.  The median is the middle score.  The mean is what most people think of as the average, and is most commonly used to measure the central tendency.

 Central Tendency is a number that describes something about the “average” score.