Exam 9: Experimental Research

Several people criticized Professor Peggy Pandemonium's experiment on "the effects of density of living conditions on aggression" for its external validity problems.This means her study had problems with

The __________ receives the treatment;the __________ does not receive the treatment.

Define the following:pre-experimental designs

Aaron Anderson studies reaction time by having participants press the space-bar on a keyboard as soon as they notice a specific word flash on a computer screen.Throughout the experiment,Aaron must carry out diagnostics and repairs to keep his equipment in working order because repetitive use makes the keyboard less sensitive and the accumulation of experimental data slows down the computer's processing speed.What threat to internal validity is Aaron contending with?

Define the following:external validity

Define the following:debrief

Define the following:post-test

Teachers Jack Black and Shannon Shack want to increase the percentage of high school freshmen who pass an algebra exam (dependent variable).They conduct experiments on five sets of classes (named A to E)in Toronto area schools.They randomly assign students and give a pretest in September followed by a post-test the following January.The treatment is teaching method.The experimental groups are taught with special in-class demonstrations and pictorial games quizzes on computers,but no homework assignments,textbooks,or tests.The control groups are taught in the traditional manner with a textbook,homework,formulas on the blackboard,and tests. Which results for a set of classes suggest that there might have been a "testing" effect from the pretest?

The Ontario provincial government banned smoking in public places and workplaces in 2004.Dr.Sandy Smokesless used public records to compare the incidence rates of lung cancers before and after 2004 to determine whether the smoking ban helped address the threat smoking poses to the health of Ontarians.What sort of experimental research is this?

What does the Hawthorne effect refer to?

In 1988,the Canadian federal government raised the speed limit to 110 km/h.Then,in 1996,individual provincial governments were given the choice to decide the highway speed limit in their own provinces and thus many raised it to 120 km/h.Proponents and critics of the law have looked at the number of traffic deaths per 1000 kilometres driven on the highways between 1988 and 1998 to see whether the law had any impact on traffic deaths.What type of design is this?

While studying rates of language acquisition for new Canadians from different countries,Curtis Cunning's research assistants informed him that 7 of the 65 subjects had quit and walked out before the study was completed.What type of threat to internal validity does Curtis' experiment have?

Sorting a collection of cases into two or more groups is referred to as _____,whereas _____ refers to selecting a smaller subset of cases from a larger pool of cases.

The Solomon four-group design combines which two other designs?

Teachers Jack Black and Shannon Shack want to increase the percentage of high school freshmen who pass an algebra exam (dependent variable).They conduct experiments on five sets of classes (named A to E)in Toronto area schools.They randomly assign students and give a pretest in September followed by a post-test the following January.The treatment is teaching method.The experimental groups are taught with special in-class demonstrations and pictorial gamesquizzes on computers,but no homework assignments,textbooks,or tests.The control groups are taught in the traditional manner with a textbook,homework,formulas on the blackboard,and tests. Which set of classes appears to have had serious "selection bias" problems in assignment to the experimental and control groups?

Define the following:Solomon four-group design

Define the following:subjects

After the delivery of a baby,new parents at Fraser Valley General Hospital were given a poison knowledge test.Before leaving the hospital they were given literature to read on poison awareness.A week later,they were invited back and took the poison test again to determine whether distributing poison awareness literature enhanced the knowledge of new parents.What kind of design is being used here?

In experimental research,what does internal validity refer to? Provide and briefly describe three examples where internal validity is an issue.

Diagram the design notation for a classical experimental design.What do each of the symbols represent?