quiz 3 Flashcards
A researcher decides to use only male participants in an experiment comparing two treatment conditions. For this study, what method is being used to control participant gender?
randomization
matching
holding constant
limiting the range
holding constant
A researcher has observed that children who eat more sugar tend to show a higher level of activity than children who eat less sugar. However, the researcher suspects that the apparent relationship may be explained by the fact that some children have a higher rate of metabolism, which causes them to eat more and to be more active compared to children with a lower rate of metabolism who eat less and are less active. This is an example of the ____.
directionality problem
third-variable problem
extraneous variable problem
manipulation check problem
third-variable problem
In an experiment, participants are usually assigned to treatments using random assignment. The reason for using random assignment is ____.
to allow the experimenter to manipulate participant variables
to allow the experimenter to manipulate environmental variables
to help control extraneous variables
to increase the reliability of the outcome measures
to help control extraneous variables
If a study finds that there is a strong relationship between two variables, this means that ____.
the first variable causes a change in the second variable
the second variable causes a change in the first variable
you can draw the conclusion that each variable causes the other variable to change
there is a relationship between the variables but causality has not been established
there is a relationship between the variables but causality has not been established
The specific treatment conditions that are used in an experiment are called the ____.
levels of the independent variable
levels of the dependent variable
control groups
manipulation checks
levels of the independent variable
Dr. Ramos is interested in studying how indoor lighting can influence people’s moods during the winter. A sample of 100 households is selected. Fifty of the homes are randomly assigned to the bright-light condition where Dr. Ramos replaces all the lights with 100-watt bulbs. In the other 50 houses, all the lights are changed to 60-watt bulbs. After two months, Dr. Ramos measures the level of depression for the people living in the houses. Assuming that the study uses people from different age groups, participant age would be a(n) ____ variable in the experiment.
dependent
independent
extraneous
confounding
extraneous
How do studies using the experimental research strategy differ from other types of research?
Only experiments can demonstrate a cause-and-effect relationship between variables.
Only experiments involve comparing two or more groups of scores.
Only experiments can describe the relationship between variables.
Only experiments can demonstrate a bi-directional relationship between variables
Only experiments can demonstrate a cause-and-effect relationship between variables.
In an experiment, manipulation of the independent variable requires ____.
creating one treatment condition defined by one level of the independent variable
creating at least two treatment conditions defined by two different levels of the
independent variable
creating at least three treatment conditions defined by three different levels of the
independent variable
measuring two separate variables to determine how they are related
creating at least two treatment conditions defined by two different levels of the
independent variable
Holding a variable constant is a technique for removing one threat to ____ but it can limit the ____ of an experiment.
internal validity; external validity
external validity; internal validity
internal validity; reliability
external validity; reliability
internal validity; external validity
Dr. Nguyen is studying how the quality of breakfast influences academic performance for elementary school children. A sample of 100 children is selected. Fifty children are provided with a nutritious breakfast when they arrive at school each morning. The other 50 children are given a doughnut each morning. After three months, Dr. Nguyen records the academic achievement level for each child and compares the two groups of scores. In this example, how many levels are there for the independent variable?
1
2
50
100
2
