Research 1

Which of these correlations permits the most accurate prediction? a. - 0.93 b. - 0.20 c. +0.81 d. +1.32

a. -0.93 A -.93 correlation permits the most accurate prediction because it has the greatest magnitude.

Psychologists use the standard deviation to report test scores. What percentage of scores falls within 1 standard deviation of the mean and what percentage falls within 2 standard deviations? a. 68%; 95% b. 75%; 99% c. 50%; 65% d. 50%; 100%

a. 68%; 95% More than 68% of scores falls within 1 standard deviation of the mean and more than 95% falls within 2 standard deviations.

The ______ of a correlation coefficient indexes its strength. a. absolute value b. direction c. probability d. sign

a. absolute value The absolute value of a correlation coefficient indexes its strength. The closer this value is to 1, the stronger the relationship between the two variables.

In order to conduct a psychology experiment, a researcher must create at least ____ treatment condition(s). a. 1 b. 2 c. 3 d. 4

b. 2 In order to conduct a psychology experiment, a researcher must create at least 2 treatment condition(s).

Which is used to determine the degree to which two or more traits, behaviors, or events are related? a. case study b. correlational study c. ex post facto study d. pretest/posttest design

b. correlational study A correlational study is used to determine the degree to which two or more traits, behaviors, or events are related. A correlational study is designed to determine the correlation between two traits, behaviors, or events. In a correlational study, a researcher obtains interval or ratio data for variables X and Y and then calculates a correlation coefficient. This design is low in manipulation of antecedent conditions and high in imposition of units.

The Pearson Product-Moment Correlation Coefficient ranges between a. 0 and -1. b. 0 and +1. c. -1 and +1. d. -2 and +2.

c. -1 and +1 The Pearson Product-Moment Correlation Coefficient ranges between -1 and +1.

The term, _______, refers to all people, animals, or objects that share at least one characteristic. a.cluster b.factor c.population d.sample

c. population The term, population, refers to all people, animals, or objects that share at least one characteristic.

Which of these is the average squared deviation of scores from the mean? a. range b. standard deviation c. variance d. mode

c. variance The variance is the average squared deviation of scores from the mean and is one of the measures of variability.

"Levels of the independent variable" refers to a.the number of dependent variables in an experiment. b. the number of independent variables in an experiment. c. the number of treatment conditions for an independent variable. d. the scale of measurement applied to the independent variable.

C. the number of treatment conditions for an independent variable. "Levels of the independent variable" refers to the number of treatment conditions for an independent variable. These are the two or more values of the independent variable manipulated by the experimenter.

An experimenter manipulates the _______ in an experiment to assess its effect on behavior. a. confounding variable b. dependent variable c. extraneous variable d. independent variable

D. Independent variable An experimenter manipulates the independent variable in an experiment to assess its effect on behavior. An independent variable is the variable (antecedent condition) that the experimenter intentionally manipulates.

To measure opinion about lowering the legal blood alcohol level to 0.08 from 0.10 grams percent, voters are randomly chosen to receive a questionnaire within selected zip codes. This is an example of a. cluster sampling. b. convenience sampling. c. quota sampling. d. stratified random sampling.

a. cluster sampling To measure opinion about lowering the legal blood alcohol level to 0.08 from 0.10 grams percent, voters are randomly chosen to receive a questionnaire within selected zip codes. This is an example of cluster sampling. Cluster sampling is a form of probability sampling in which a researcher samples entire clusters, or naturally occurring groups, that exist within the population.

The _______ is the specific behavior we expect to change due to our experimental intervention. a. dependent variable b. extraneous variable c. independent variable d. subject variable

a. dependent variable The dependent variable is the specific behavior we expect to change due to our experimental intervention

In a "true" experiment, an experimenter _______ the independent variable and _______ the dependent variable. a. manipulates; measures b. measures; manipulates c. selects; manipulates d. selects; measures

a. manipulates; measures In a "true" experiment, an experimenter manipulates the independent variable and measures the dependent variable.

What does a sample's representativeness affect? a. the ability to generalize experimental findings b. the experimental design c. the internal validity of experimental findings d. the statistics used to analyze experimental data

a. the ability to generalize experimental findings A sample's representativeness affects the ability to generalize experimental findings. Representativeness is the extent to which the sample responses we observe and measure reflect those we would obtain if we could sample the entire population.

Why do researchers randomly assign subjects to experimental conditions? a. to control individual differences b. to control demand characteristics c. to prevent confounding by order d. to control progressive error

a. to control individual differences Researchers randomly assign subjects to experimental conditions to prevent confounding due to subject variables like intelligence.

Which relationship best illustrates a negative correlation? a. height and weight b. years of education and income c. IQ and GPA d. automobile engine size and fuel economy

d. automobile engine size and fuel economy The relationship between automobile engine size and fuel economy best illustrates a negative correlation. A negative correlation is a relationship existing between two variables such that an increase in one is associated with a decrease in the other; also called an inverse relationship.

We do not know which population our sample represents when we use a. cluster sampling. b. convenience sampling. c. quota sampling. d. convenience sampling or quota sampling.

d. convenience sampling or quota sampling We do not know which population our sample represents when we use convenience sampling or quota sampling. This is because these procedures use nonprobability sampling procedures in which subjects are not chosen at random.

Statisticians prefer probability samples over nonprobability samples because they a. are less time consuming. b. are normally distributed. c. increase the internal validity of our studies. d. often better represent the population of interest.

d. often better represent the population of interest Statisticians prefer probability samples over nonprobability samples because they often better represent the population of interest. A probability sample involves selecting samples in such a way that the odds of any subject being selected for the study are known or can be calculated.

A researcher randomly selects every tenth name from a list of ADHD patients. These adolescents constitute a _____ or subset of the population from which they were drawn. a. cluster b. cohort c. factor d. sample

d. sample A researcher randomly selects every tenth name from a list of ADHD patients. These adolescents constitute a sample or subset of the population from which they were drawn. A sample is a selected subset of the population of interest.

The relationship between_______ best illustrates a positive correlation. a. alcohol consumption and driving performance b. aspirin use and risk of heart attack c. exercise frequency and depression d. wearing seat belts and life expectancy

d. wearing seat belts and life expectancy The relationship between wearing seat belts and life expectancy best illustrates a positive correlation. A positive correlation is the relationship between two measures such that an increase in the value of one is associated with an increase in the value of the other; also called a direct relationship.