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