Exam 24: Evaluating Research Validity: Part II

A researcher predicted that music training would enhance young children's spatial-temporalreasoning. 88 preschool children participated in the study. They were randomly assigned to oneof three conditions: 30 children received private music lessons, 29 children received computerlessons, and 29 children were the controls. A standardized test, the Wechsler Preschool andPrimary Scale of Intelligence (WPPSI), was used to measure spatial-temporal reasoning beforeand immediately after the interventions. The WPPSI is evaluated positively in Buros MentalMeasurements Handbook and has been used in hundreds of studies on preschoolers' reasoningskills. All tasks were independently scored by two researchers blind to condition assignment.Interobserver reliability was r =.95. Significant improvement was found for the private musicgroup only. The researcher stated that this study demonstrates that music training produces longterm modifications in underlying neural circuitry, and improvement of this type may enhance thelearning of mathematics and science -Rate the equivalence of the groups on participant characteristics:

What is the difference between a population, selected sample, and actual sample?

A study's validity can be reduced if one or more key measures show little evidence of reliability.

Extraneous variables are well controlled in comparative and associational studies.

A researcher predicted that music training would enhance young children's spatial-temporalreasoning. 88 preschool children participated in the study. They were randomly assigned to oneof three conditions: 30 children received private music lessons, 29 children received computerlessons, and 29 children were the controls. A standardized test, the Wechsler Preschool andPrimary Scale of Intelligence (WPPSI), was used to measure spatial-temporal reasoning beforeand immediately after the interventions. The WPPSI is evaluated positively in Buros MentalMeasurements Handbook and has been used in hundreds of studies on preschoolers' reasoningskills. All tasks were independently scored by two researchers blind to condition assignment.Interobserver reliability was r =.95. Significant improvement was found for the private musicgroup only. The researcher stated that this study demonstrates that music training produces longterm modifications in underlying neural circuitry, and improvement of this type may enhance thelearning of mathematics and science -The accessible population is:

A masked review indicates that peer experts reviewed an article without knowing the author.

Articles in popular magazines have been peer reviewed.

A major limiting factor to using complex associational analyses is the number of participants required.

Internal validity and evidence for causation are influenced by the research approach.