Good research generates dependable data. Psychology is a scientific study that uses the scientific method (an organized way of using experience and testing ideas to expand and refine knowledge. Psychologists begin with a research question which comes from folklore, daily experience, or psychological theory. The biggest trick to psychological research is providing the operational definitions for the variables under study. Ex. A study on the effects of television violence on children creates a challenge of deciding which shows are violent and how much television watching is a lot.
Conducting research has many angles that can be taken. Most psychologists would agree that the best method of answering cause and effect questions is through an experiment. It allows psychologists to control experience of subjects and draw conclusions about cause and effect.
The experimental method begins with variables (properties being studied). Independent variable is the condition in a study that is manupulated so its effects may be observed. The dependent variable ia a measure of an assumed effect of an IV. It is normally assumed that the IV causes the DV to occur. The experimental and control groups are next to be developed. The experimental group recieves the treatment, while the control group does not. These groups are to be drawn as a sample of the population. Their are two types of sampling: random and stratified. Random is where each member of a population has an equal chance of being selected to participate. The stratified sample is an identified subgroup within the population. The two types of experiments asked for on the AP Exam are blind and double-blind. The blind experiment is when subject is unaware of receiving treatment, and the double-blind experiment is when experimenter and subject are unaware of those receiving treatment.
There are other controlled ways that psychologists use to answer questions. The case study is a carefully drawn biography that is obtained through interviews, questionaires, and psychological tests. The survey is a scientific investigation in which a large sample of people answer questions about their behavior or attitudes. Naturalistic observation observes organisms in their natural surroundings (unobtrusive and obtrusive). The correlation method studies the relationships between variable. The correlation coefficient varies between +1.00 and -1.00. In psychology it is used to determine validity and reliability. Know the difference between negative, positive and no correlation.
Practice Essay, along with a full credit answer. Try it without looking at the answer first.
Other terms to know: observer effect, observer bias, extraneous and confounding variables, hypothesis
Statistics-the tools researchers use to analyze and summarize large amounts of data
Descriptive Statistics: numbers used to present a collection of data in a brief yet meaningful form.
A frequency distribution is the range of scores we get and the frequency of each one when we measure a sample of people regarding some trait. They are often represented in a graphic form so their patterns can be seen at a glance. A normal distribution is represented as a normal curve. A normal curve is a graph of a frequency distribution in which the curve tapers off equally on either side of a central high point. Skewed distributions are distributions in which more data fall toward one side of the scale than toward the other. They have a tail on one end and are not symetrical. When the tail is on the right is is positively skewed and when the tail is on the left it is negatively skewed.
Measures of central tendency: the three measures are mean, median and mode. The mean is the arithmetic average of all the individual measurements in a distribution. The median is the score above and below which half the scores in the distribution fall. The mode is the most frequent measurement in a distribution of scores.
Measures of variability: It tells us to what extent the scores in a distribution are spread out. One measure of variability is the range. The range consists of the two most extreme scores at either end of the distribution. It's obtained by subtracting the two. Another measure is standard deviation, which shows how widely all the scores in a distribution are scattered above and below the mean. If scores cluster closely around the mean, the standard deviation will be small and vice versa. It tells us how represenative the mean is. Translation: how far on average is each score from the mean?
Inferential Statistics: they assist us in determining whether we can generalize differences among samples to the populations that they represent. If we could not draw inferences about populations from studies of samples, our research findings would be limited indeed. We would only be able to speak of the individuals studied.
An example would be a Head Start program that obtained findings that their program raised IQ scores. Students enrolled obtained a mean IQ score of 99, whereas children similar in background who were not enrolled obtained a mean IQ score of 93. Is this significant, or does it represent a chance fluctuation in scores? The farther apart a groups mean is, the more statistically significant it is.
