APK4050 Ch.6 (Quiz 2)

Threat to internal validity: testing

beneficial practice effects for repetitions of the same test any test that measures skill, or those that would be influenced by motivation, stress tests, both tests with no treatment between will tell how much is due to pre test and how much is due to intervention

Threat to internal validity: selection bias

comparison groups are not equal at the beginning of the study

Threats to external validity: multiple treatment interference

experiencing one treatment affects participant response to a subsequent treatment

Threats to internal validity (9)

history, maturation, testing, instrumentation, statistical regression, selection bias, experimental mortality, selection-maturation interaction, expectancy

Threats to external validity (4)

interaction effect of testing, interaction of selection bias and experimental treatment, reactive effects of experimental setting, multiple treatment interference

Threat to internal validity: experimental mortality

loss of participants from a study for any reason i.e. could be normal withdrawal

Threat to internal validity: selection -maturation interaction

maturation affects groups within the study differently a kid could get better because he or she is developing, but an older person would degrade because he or she is getting older

Threat to internal validity: instrumentation

negative effects of reliability problems with equipment or observers

Threat to internal validity: statistical regression

tendency of extreme scores to regress toward the mean upon retest highest scores get lower and lowest scores get higher

Threats to external validity: interaction of selection bias and experimental treatment

a biased sample produces skewed results not representative of the population; offering a free VO2 max test will attract a lot of athletes

Threat to internal validity: maturation

effects related to the passage of time, such as aging especially important in adolescents

Threat to internal validity: expectancy

rater expectations influence data avoid this with a double blind

Threats to external validity: reactive effects of experimental setting

some element of the setting causes modification of participant behavior activity monitor example and food intake diary example

Threat to internal validity: history

something occurring over time (other than the experiment) that could affect the dependent variable other things that they do could affect the outcome, to avoid this give them clear instruction on how to act and what to do during the examination

Threats to external validity: interaction effect of testing

the pretest changes the group's response to the experimental treatment don't provide pre test results: if you have high cholesterol you may subconsciously change habits