Unit 2—The Research Enterprise in Psychology

1. Briefly identify and describe the three goals of the scientific enterprise. (p. 42)
   
   Measurement and description: investigator must figure out a way to measure the phenomenon under study. First goal of psych is to develop measurement techniques that make it possible to describe to describe behavior clearly and precisely.
   understanding and prediction: scientists try to understand event and the reason for their occurrence.
   Application and control:Scientists hope that the information they gather will be of some practical value in helping to solve everyday problems. 
   
2. Define “hypothesis,” “variables,” and “theory.” What is required of a
   scientific theory? How are scientific theories constructed? (pp. 42-44)
   Hypothesis is a tentative statement about the relationship between two or more variables.
   Variables are any measurable conditions, events, characteristics, or behaviours that are controlled or observed in a study.
   Theory is a system of interelated ideas and explain a set of observations. Theories help psychologists make the leap between from the description of behavior to the understanding of behavior. The enhanced understanding of theories guides future research by generating new predicitions and suggesting new lines of inquiry. 
   Scientific theory must be testable. 
   
3. Identify and describe the five steps in scientific investigations, as outlined by Weiten and McCann. (pp. 44-45)
    Formulate testable hypothesis: the first step in a scientific investigation is to translate a theory or an intuitive idea into a testable hypothesis. Normally, hypotheses are expressed as predictions. To be testable, scientific hypotheses must be formulated precisely and the variables under study must be clearly defined. Researchers achieve these clear formulations by providing operational definitions of the relevant variables. Operational definition establish precisely what is meant by each variable in the context of the study.
   Select  the research and design the study: The second step is to figure out how to put the hypothesis to an empiracal test. The research method chosen depends greatly on the nature of the question under study.
   Collect the data: third step is to collect date.
   Analyze data and draw conclusions: researchers use statistics to analyze their data and decide whether their hypotheses have been supported. Thus, statistics play an essential role in the scientific enterprise.
   Report the findings: the final step in a scientific investigation is to write up a concise summary of the study and its findings. They write a report and submit it to journals for publication for critical evaluation. If flaws are serious enough, the results may be discounted or discarded.
   
   
4. Define “operational definition,” “participants (or subjects),” and “data collection techniques.” (pp. 44-45)
    Operational definition establish precisely what is meant by each variable in the context of the study.
   Participants are the persons or animals whose behavior is systematically observed in a study
   data collection techniques are procedures for making empirical observations and measurements. 
   
   Comment: In everyday life, people often words casually. For example, if we describe ourselves as feeling “full of anxiety,” our listeners will usually get the general idea of what we mean. This practice is not precise enough for psychological research, however. If we use the word “anxiety” in psychological research, we must define it operationally, in terms of the actions or operations used to measure anxiety. For example, anxiety might be measured using physiological measures, such as heart rate and perspiration, or it might be measured using a test in which people rate the extent of their anxiety. The same generally goes for other variables in a psychology experiment: they must be defined precisely through the operations that are used to measure them.
   
5. Describe two advantages of the scientific approach as it relates to the study of behaviour. (p. 47)
    Scientific approach offer clarity and precision as well as being intolerant of error.
   
   Comment: The two features of a scientific approach with respect to behaviour are: (a) an insistence on clarity and precision, and (b) avoidance of errors. To avoid errors, scientists take a skeptical attitude, which entails believing things only after they have been proven through experiments or other means of generating data. Scientific skepticism is a way to guard against accepting false data, incorrect facts, and bogus causal relationships. However, once data, facts, and causal relationships have passed the test of skepticism, scientists can then accept these findings as fully and passionately as they formerly were skeptical about them. Be careful not to think of scientists as being skeptical about everything. Scientists restrict their skepticism to that which has not been proven, and they accept what has been proven. This restrictive skepticism enables scientists to assemble proven facts in understanding the world.

1. Define “experiment.” Define and give examples of the three types of variables (dependent, independent, extraneous) that are encountered in an experiment. (pp. 48-49)
   
   Experiment is a research method in which the investigator manipulates a variable under carefully controlled condidtions and observes whether any changes occur in a second variable as a result.
   An independent variable is a condidtion or event that an experimenter varies in order to see its impact on another variable. It is the variable that the investigator controls or manipulates.
   Dependent variable is the variable that is thought to be affected by manipulation of the independent variable. In psych, the dependent variable is usually a measurement of some aspect of the participants behavior.
   
2. Distinguish between experimental and control groups, and explain their relationship in an experiment. (pp. 48-4
   Experimental group consists of the subjects who receive the some special treatment in regard to the independent variable. The control group consists of similar subjects who do not receive the special treatment given to the experimental group.
   It is crucial that the experimental and control group be alike., expect for the treatment that they receive in regard to the independent variable.
3. Define “confounding of variables.” (p. 49)
   A confounding of variables occurs when two variables are linked in a way that makes it difficult to sort out their specific effect.
   
4. Define “random assignment of subjects.” (p. 49)
   Random assignment of subjects occurs when all subjects have an equal chance of being assigned to any group or condition in the study.
   
5. Why is it sometimes advantageous to use only one group of subjects who serve as their own control? (p. 50)
   Comment: Although Weiten and McCann (2007) do not specifically identify them as such, two broad types of experimental design are used in psychology:
   
   1. between-subjects design
   2. within-subjects design
   The between-subjects design typically involves an experimental group of subjects and at least one control group of subjects. For example, the subjects in an experimental group might be given the drug the researcher is interested in testing, while the subjects in the control group are given a placebo. The researcher will then check to determine whether any significant differences exist between the two groups of subjects.
   The within-subjects design does not require a separate control group. In this design, one group of subjects (or even a single subject) acts as their own control. Thus, the researcher might take repeated measures of each subject’s response to different experimental conditions. For example, each subject might be given the placebo first, then the drug the researcher is interested in testing, then the placebo again. This approach is known as an A-B-A design. These designs are useful because they show the effects of a variable on an individual subject rather than on a hypothetical “average subject.”

 It is sometimes advantageous to use only group of subjects who serve as their own control group for 3 reasons.
1. the effects of the independent variable are evaluated by exposing this single group to different conditions--an experimental condition and a control condition.
2. It is possible to manipulate more than independent variable in a single experiment
3. It is also possible to use more than one dependent variable in a single study.

1. Is it possible to use more than one independent variable in a single experiment? Explain. Provide and recognize original examples of this situation. (p. 50)

 It is possible to use more than one independent variable in a single experiment. Researches often manipulate two or three independent variables to examine their joint effect on the dependent variable. In the Dulton experiement the hight of bridge and gender of confederate were independent variables.

1. What is an interaction? (p. 50)
   Interaction means that the effect of one variable depends on the effect of another. 
   
2. Is it possible to use more than one dependent variable in a single experiment? Explain. Provide and recognize original examples of this situation. (p. 50)
   
   Researchers frequently use a number of dependent variables to get a more complete picture of how experimental manipulations affect subjects behavior. In Dulton experiment, they used botha questionaire and a behavioral measure. 
   
3. Discuss the major advantages and disadvantages of the experimental method. (p. 51)
   
   Principal advantage is that it permits conclusions about cause and effect relationship between variables. Researchers are able to draw conclusions about causation because the precise control available in the experiment allows them to isolate the relationship between independent and dependent variable, while neutralizing the effects of extraneous variable.
   
   One disadvantage is that the experiment is often aritifical.
   Another disadvantage is the experimental method can't be used to explore some research questions.
   
4. Distinguish between the experimental and the descriptive/correlational research methods. Discuss three descriptive research methoesds: naturalistic observation, case studies, and surveys. (pp. 52-55)
    Descriptive research aims to describe something
   
   

   Data is used to describe components or characteristics.
   		In descriptive research hypotheses are typically speculative. (Aaker and Day)
   		There is no explicit cause and effect relationship - all that is shown is that two variables are related. (Aaker and Day)

     Experimental research allows one to make causal inferences about relationships among variables
   
   

   The purpose of experimental research is to "show that one variable causes or determines the values of other variables." (Aaker and Day)
   		Experimental research is conducted under controlled conditions so as to rule out alternative reasons for observed relationships.
   		In experimental research, controls and variable manipulation are used to ascertain causal relationships.
   		Research questions and hypotheses are very specific.

5. 
   Discuss the major advantages and disadvantages of descriptive/correlational research. What is the strongest disadvantage of descriptive/correlational research? (pp. 55-57)

Advantage: they give researchers a way to explore questions that could not be examined with experimental procedures. Descriptive/correlational research broadens the scope of phenomena that psychologists are able to study. 
Disadvantage: investigators cannot control event to isolate cause and effect. Consequently correlational research cannot demonstrate conclusively that two variables are casually related.

1. What are statistics? What are descriptive statistics? (p. 57)

Statistics is the use of mathematics to organize, summarize, and interpret numerical data. Allows researchers to draw conclusions based on their observations.
Descriptive statistics are used to organize and summarize data. They provide an overview of numerical data. 

1. What is central tendency? Define and describe the three measures of central tendency: the median, the mean, and the mode. Which of these measures is most useful? Which measure is unduly influenced by extreme scores? (p. 57)

Central tendency allows researchers to know what constitues a typical score. To do this they use 3 measures of central tendency
median: the scroe that falls exactly in the center of a distribution of score
mean: the arithmetic average of the scores in a distribution
mode: the most frequent score in a distribution.
The mean is the most useful because additional stastistical manipulations can be performed on it. However the mean is sensitive to extreme score in a distribution which can sometimes make the mean misleading. 

1. Define “variability.” What, in general terms, is a standard deviation? What does a large standard deviation indicate about variability? What does a small standard deviation indicate about variability? (pp. 57-58)

Variability refers to how much the scores  in a data set vary from each other and from the mean. The standard deviation is an index of the amount of variability in a set of data.When variability is great, the standard deviation will be relatively large. When variability is is low, the standard deviation will be smaller.

1. When is a correlation said to exist? What is a correlation coefficient? What is a positive correlation? What is a negative correlation? What is the strength of the correlation, and how is this indicated in the correlation coefficient? (pp. 58-59)

 A correlation exists when two variables are related to each other. The correlation coefficient is a numerical index of the degree of relationship between two variables. A correaltion coefficient indicates the direction (positive or negative) of the relationship and how strongly the two variables are related. A positive correlation indicates that two variables co-vary in the same direction. This means that high scores on variable x are associated with hogh scores on variable y. A negative correlation indicates that two variable co-vary in the opposite direction. This means people who score high on variable x tend to score low on variable y. If the correation is negative a minus is always placed in front of the coefficient. A plus sigh may be shown if it is positive.

The size of the coefficient indicates the strength or ans association between or and +1.00 or 0 and -1.00. A correlationship near zero indicates no relationship near variables.