Section 1: What Is Research? Chapter Introduction Section 1: What Is Research? Section 2: Problems and Solutions in Research Section 3: Statistical Evaluation Chapter Menu

Main Idea Psychologists must first decide how to approach the research issue. Then psychologists conduct the research in one of a variety of ways to test a hypothesis, solve a problem, or confirm previous findings. Section 1-Main Idea

Pre-Research Decisions Researchers begin by asking a specific question about a limited topic or hypothesis. Then they collect evidence. A sample is a relatively small group of the total population under study. A sample must be representative. Section 1

Pre-Research Decisions (cont.) Ways to avoid a nonrepresentative sample: Take a purely random sample. Deliberately pick individuals who represent the various subgroups in the population being studied, also known as a stratified sample. Jane Goodall Section 1

Methods of Research The goals of research are to: Describe behavior Explain its causes Predict the circumstances under which certain behaviors may occur again Control certain behaviors Section 1

Methods of Research (cont.) Methods of research used to accomplish these goals: Naturalistic observations Case studies Surveys Longitudinal Studies Cross-Sectional Studies Correlations Experiments – Controlled environment A Correlation Study Section 1

naturalistic observation: research method in which the psychologist observes the subject in a natural setting without interfering Direct observation ? Vocab2

case study: research method that involves an intensive investigation of one or more participants Vocab3

survey: research method in which information is obtained by asking many individuals a fixed set of questions Vocab4

longitudinal study: research method in which data are collected about a group of participants over a number of years to assess how certain characteristics change or remain the same during development Vocab5

cross-sectional study: research method in which data are collected from groups of participants of different ages and compared so that conclusions can be drawn about differences due to age Vocab6

correlation: the measure of a relationship between two variables or sets of data Vocab7

A Correlation Study These charts display possible correlations between different variables. Figure 1

Experimental Research Psychology is an experimental science. Psychologists follow the same general procedures when conducting experimental research. Figure 2

DFS Trans 1

Section 1-Polling Question Which of the following do you think is the best method of research? A. Naturalistic observation B. Case study C. Survey D. Longitudinal study A B C D Section 1-Polling Question

Methods of Research (cont.) Every experiment has: hypothesis variables (independent and dependent) experimental group control group Experimental Research Section 1

hypothesis: an educated guess about the relationship between two variables Vocab8

variable: any factor that is capable of change Vocab9

experimental group: the group to which an independent variable is applied Vocab10

control group: the group that is treated in the same way as the experimental group except that the experimental treatment (the independent variable) is not applied Vocab11

What is the importance of a control group? A. It exhibits change during an experiment. B. It affects the results in the experimental group. C. It allows for a comparison to identify changes in the experimental group. D. None of the above. A B C D Section 1

Methods of Research (cont.) Ethics are the methods of conduct, or standards, for proper and responsible behavior. The APA has a list of ethical principles that psychologists must follow. Section 1

Section 2-Polling Question Do you think that expectations of behavior affect actual behavior? A. Yes B. No A B Section 2-Polling Question

Problems and Solutions in Research A self-fulfilling prophecy is a situation in which a researcher’s expectations influence that person’s own behavior, and thereby influence the participant’s behavior. Section 2

Avoiding a Self-Fulfilling Prophecy Ways to avoid self-fulfilling prophecy: Single-blind experiment Double-blind experiment Single-Blind and Double-Blind Experiments Section 2

single-blind experiment: an experiment in which the participants are unaware of which participants received the treatment Vocab13

double-blind experiment: an experiment in which neither the experimenter nor the participants know which participants received which treatment Vocab14

DFS Trans 2

Single-Blind and Double-Blind Experiments Researchers must take measures during experimentation to guard against seeing only what they expect to see. Figure 3

Do you agree or disagree that humans often have preconceived notions about what will happen in a situation? A. Agree B. Disagree C. Not sure A B C Section 2

The Milgram Experiment In the 1960s, Stanley Milgram wanted to determine whether participants would administer painful shocks to others merely because an authority figure had instructed them to do so. The result implied that ordinary individuals could easily inflict pain on others if such orders were issued by a respected authority. Section 2

The Milgram Experiment (cont.) His experiment, although no one was actually shocked, was controversial. Today, experiments are required to submit a plan to a Human Subjects Committee. Section 2

Do you believe that Milgram’s decision to use volunteers as he did was ethical or unethical? A. Ethical B. Unethical C. Not sure A B C Section 2

The Placebo Effect The placebo effect is a change in a participant’s illness or behavior that results from a belief that the treatment will have an effect rather than from the actual treatment. Section 2

Do you think that is ethical to use a placebo in an experiment? A. Yes B. No C. Not sure A B C Section 2

Statistical Evaluation Statistics consist of the branch of mathematics concerned with summarizing and making meaningful inferences from collections of data. Kate’s Data Section 3

Kate’s Data Kate’s data show the number of hours of television watched before and after the quiz, the grade on the quiz, the number of products recognized, and participants’ height in inches. * Highest grade possible is 10. Figure 4

Section 3-Polling Question In your opinion, in which way are statistics more likely to be used? A. To distort the truth B. To honestly support a hypotheses A B Section 3-Polling Question

Descriptive Statistics Descriptive statistics involve the listing and summarizing of data in a practical, efficient way. One of the first steps that researchers take to organize their data is to create frequency tables and graphs. Section 3

Descriptive Statistics (cont.) A frequency distribution is a way of arranging data so that we know how often a particular score or observation occurs. A Frequency Distribution Section 3

A Frequency Distribution A frequency distribution shows how often a particular observation occurs. Figure 5

Descriptive Statistics (cont.) Types of graphs: Histogram Frequency polygon/frequency curve A Frequency Polygon Section 3

Concept Trans 2

A Frequency Polygon This graph shows the number of hours of TV watched the night before the quiz and the night after the quiz. Figure 6

Descriptive Statistics (cont.) A normal curve is a graph of frequency distribution shaped like a symmetrical, bell-shaped curve. A Normal Curve Section 3

A Normal Curve The maximum frequency lies in the center of a range of scores in a perfect normal curve. The frequency tapers off as you reach the edges of the two sides. Figure 7

Descriptive Statistics (cont.) A common way of summarizing is to measure the central tendency. – A number that describes something about the “average” score of a distribution. Distributions also differ in their variability. – Measuring the difference, or spread of data. Measure of Central Tendency Section 3

Measures of Central Tendency It is often useful to summarize a set of scores by identifying a number that represents the center, average, or most frequently occurring number of the distribution. Figure 8

In relation to class test scores, which of the following do you think is more descriptive? A. An average of 84 B. A median of 85 C. A mode of 79 A B C Section 3

Descriptive Statistics (cont.) Two commonly used measures of variability are: Range – subtract the lowest number in a data set from the highest number and add 1. (“crude” measurement) Standard deviation Standard Deviation Section 3

standard deviation: a measure of variability that describes an average distance of every score from the mean Vocab22

Standard Deviation Two distributions with the same mean and different standard deviations are shown. Figure 9

Descriptive Statistics (cont.) Standard deviation is a better measure because it uses all of the data points. A correlation coefficient describes the direction and strength of the relationship between two sets of observations. The most commonly used measure is the Pearson correlation coefficient (r). Section 3

Descriptive Statistics (cont.) A coefficient with a plus sign (+) indicates a positive correlation. A coefficient with a minus sign (–) indicates a negative coefficient. A scatterplot is a graph of scores that demonstrates the direction of the relationship between two variables. A Scatterplot Section 3

Concept Trans 1

A Scatterplot When there is little or no relationship between two variables, the points in the scatterplot do not seem to fall into any pattern. Figure 10

Inferential Statistics (cont.) Many researchers say that if the probability that their results were due to chance is less than 5%, they do not think the results were due to chance. The results would then be considered statistically significant. Section 3