Psyc Ch 1

How can we describe data with measures of central tendency and variation?

A measure of central tendency is a single score that represents a whole set of scores. Three such measures are the mode (the most frequently occurring score), the mean (the arithmetic average), and the median (the middle score in a group of data). Measures of variation tell us how diverse data are. Two measures of variation are the range (which describes the gap between the highest and lowest scores) and the standard deviation (which states how much scores vary around the mean, or average, score). Scores often form a normal (or bell-shaped) curve.

How do psychologists use case studies, naturalistic observation, and surveys to observe and describe behavior, and why is random sampling important?

Descriptive methods, which include case studies, naturalistic observations, and surveys, show us what can happen, and they may offer ideas for further study. The best basis for generalizing about a population is a representative sample; in a random sample, every person in the entire population being studied has an equal chance of participating. Descriptive methods cannot show cause and effect because researchers cannot control variables.

How do hindsight bias, overconfidence, and the tendency to perceive order in random events illustrate why science-based answers are more valid than those based on intuition and common sense?

Hindsight bias (also called the "I-knew-it-all-along phenomenon") is the tendency to believe, after learning an outcome, that we would have foreseen it. Overconfidence in our judgments results partly from our bias to seek information that confirms them. These tendencies, plus our eagerness to perceive patterns in random events, lead us to overestimate our intuition. Although limited by the testable questions it can address, scientific inquiry can help us overcome our intuition's biases and shortcomings.

What are positive and negative correlations, and why do they enable prediction but not cause-effect explanation

In a positive correlation, two factors rise or fall together. In a negative correlation, one item rises as the other falls. Scatterplots can help us to see correlations. A correlation coefficient can describe the strength and direction of a relationship between two variables, from +1.00 (a perfect positive correlation) through zero (no correlation at all) to −1.00 (a perfect negative correlation). A correlation can indicate the possibility of a cause-effect relationship, but it does not prove the direction of the influence, or whether an underlying third factor may explain the correlation

How do theories advance psychological science?

Psychological theories are explanations that apply an integrated set of principles to organize observations and generate hypotheses—predictions that can be used to check the theory or produce practical applications of it. By testing their hypotheses, researchers can confirm, reject, or revise their theories. To enable other researchers to replicate the studies, researchers report them using precise operational definitions of their procedures and concepts. If others achieve similar results, confidence in the conclusion will be greater.

Can laboratory experiments illuminate everyday life?

Researchers intentionally create a controlled, artificial environment in the laboratory in order to test general theoretical principles. These general principles help explain everyday behaviors.

Why do psychologists study animals, and what ethical guidelines safeguard human and animal research participants?

Some psychologists are primarily interested in animal behavior; others want to better understand the physiological and psychological processes shared by humans and other species. Government agencies have established standards for animal care and housing. Professional associations and funding agencies also establish guidelines for protecting animals' well-being. The APA ethics code outlines standards for safeguarding human participants' well-being, including obtaining their informed consent and debriefing them later.

How do the scientific attitude's three main components relate to critical thinking?

The scientific attitude equips us to be curious, skeptical, and humble in scrutinizing competing ideas or our own observations. This attitude carries into everyday life as critical thinking, which puts ideas to the test by examining assumptions, discerning hidden values, evaluating evidence, and assessing conclusions

What are the characteristics of experimentation that make it possible to isolate cause and effect?

To discover cause-effect relationships, psychologists conduct experiments, manipulating one or more factors of interest and controlling other factors. Using random assignment, they can minimize confounding variables, such as preexisting differences between the experimental group (exposed to the treatment) and the control group (given a placebo or different version of the treatment). The independent variable is the factor the experimenter manipulates to study its effect; the dependent variable is the factor the experimenter measures to discover any changes occurring in response to the manipulations. Studies may use a double-blind procedure to avoid the placebo effect and researcher's bias.

How do we know whether an observed difference can be generalized to other populations?

To feel confident about generalizing an observed difference to other populations, we would want to know that the sample studied was representative of the larger population being studied; that the observations, on average, had low variability; that the sample consisted of more than a few cases; and that the observed difference was statistically significant.