PSY141 Chapter 11

Suppose you read a news report that a study was conducted where people who reported drinking green tea each day as a part of their diet were less likely to be diagnosed with cancer over the 5 years the study took place. Why can't we conclude that drinking green tea makes one less likely to develop cancer? Develop 2 possible explanations for the results reported from the study.

This is a correlational study. No independent variable was manipulated, and other possible factors that could affect cancer rates were not controlled for. Thus, we cannot conclude that drinking green tea has a causal relationship with cancer rates. It is possible that it does, or it is possible that people who are less likely to get cancer (e.g., no family history) are more likely to drink green tea (i.e., low cancer probability causes one to drink green tea). Finally, it is possible that a third variable (e.g., maintaining a healthy lifestyle) causes one to both drink green tea and have low likelihood of getting cancer.

A negative relation is shown by a downward slope of the cluster of data points in a graph of the data set.

True

At times, correlational studies are the only options because we cannot subject study participants to factors that may negative impact their health for ______. confidentiality reasons anonymity reasons ethical reasons recruitment issues

ethical reasons

Important information can be gained from correlational studies about the likelihood of an event based on the relationship with another event, but this relationship may or may not be ______. positive negative causal predictive

causal

In ______ studies, researchers examine two or more measures to determine if those measures are related. correlational descriptive predictive analytical

correlational

Most of the research showing a link between smoking and long-term health in humans has involved ______ studies. correlational descriptive predictive analytical

correlational

When a variable that is not of interest in a study may explain the results of a study is a ______. high internal validity third variable problem experimenter bias low reliability

third variable problem

Suppose a study was conducted to examine the relationship between how often people exercise and how happy they are with their lives. Participants in this study were asked to report how many times they exercise for 30 min or more at a time and to complete a questionnaire with items that measure their quality of life. A positive relationship is found between the number of times per week people exercise and their quality of life score. a) what are the dependent variables in this study? b) describe the three different types of causal relationships that could exist between the dependent variables c) explain why this study does not provide evidence ofr any of the causal relationships you described in b.

(5a) How often people exercise measured by how many times per week they exercise for 30 minutes or more at a time and happiness measured by the score on the quality of life scale. (5b) more exercise may cause people to be happy, being happy could cause people to exercise more, or some third variable could cause both happiness and more exercise. (5c) no variable is manipulated in this study; thus, no causal relationships are tested. One of the variables (it would be easiest to manipulate the amount of exercise variable) must be manipulated (e.g., participants randomly assigned to different conditions of the variable) to test a causal relationship.

Correlational studies are not well-suited for answering _________ research questions. (a) causal (b) descriptive (c) predictive (d) none of the above (they can be used for any research question).

(a) causal

Suppose that a researcher found that as introversion (as measured on a standardized questionnaire) of participants goes up, number of social activities attended per week decreases. This finding represents (a) a positive relationship. (b) a negative relationship. (c) no relationship. (d) none of the above.

(b) a negative relationship.

Explain the differences between a descriptive research question and a predictive research question. Provide an example of each.

A descriptive research question is one where a researcher is interested in whether a behavior occurs and how often it occurs. In a correlational study, a descriptive research question might be whether a relationship exists between two variables and what type of relationship exists. A predictive research question is one in which a researcher examines whether one variable can be predicted from one or more variables.

For the study described previously explain how the researchers could have done a study to test the causal relationship between drinking green tea and incidence of cancer.

An experiment would need to be conducted where the researcher randomly assigns participants either to drink green tea every day or to not drink any green tea (but perhaps to drink a similar-looking drink that they are told is green tea but is actually just colored water) and then records who gets cancer in order to compare cancer rates across the two groups.

How are correlational studies different from quasi-experiments?

Correlational studies measure dependent variables from a single group of subjects to look for relationships between the measures, but do not separate subjects into groups for comparison as is done in quasi-experiments.

Correlation equals causation.

False

If two factors simply co-occur, this indicates a causal relationship.

False

In a correlational study, the variable that is predicted by the predictor variable is called the ______ variable. outcome dependent confounding third

outcome

When two measures are related such that, as the value of one measure increases the value of the other measure also increases, this is called a _________ relationship

positive

A research question that asks if one behavior can be predicted from another behavior to allow predictions of future behavior is a ______ research question. positive negative descriptive predictive

predictive

if you are attempting to determine the calue of one measure based on its relationship with another measure, you are testing a _____________ research question

predictive